Release notes/0.46

Inkscape 0.46

Highlights in this release:

• Paintbucket tool

• Tweak tool

• 3D Box tool

• Live path effects

• Color management

• New SVG filters and UI

• Native PDF and AI import

• XAML import/export

• Open Clip Art Library integration (import/export)

• Stock patterns

• Bitmap editing extension effects

• Full on-canvas gradient editing

• Engraver's Toolbox in the Calligraphic tool

• Touch selection

• Dockable dialogs

• Command-line access to verbs

• Snapping made usable

• "3D" / axonometric grid

• Angled guidelines

• Conversion of objects to guidelines

• Significant speed and interactivity improvements

• Hundreds of smaller features and bugfixes

Speed and interactivity

• In this version, Inkscape starts using the cairo library for rendering. It is now used for outline mode display which, thanks to using cairo and other optimizations, redraws faster by about 25%. More impressive are memory savings: thanks to cairo, in outline mode Inkscape now takes only about 50% of the memory used by 0.45 for the same file.

• Smart redraw directionality: With complex images and/or on slow computers, you may have noticed that Inkscape redraws the screen image in horizontal strips, and these strips are painted in order from top to bottom. Now the redraw always starts at your mouse cursor location and proceed upwards and downwards from it, so that the area near the cursor is always redrawn first. This significantly improves program's responsiveness in some situations. For example, when you are node-editing part of a complex path, the entire path needs to be redrawn on each change, but now this redraw starts from the point you're working on. Moreover, the redraw is interruptible, so each mouse movement starts new redraw from the mouse cursor area. As a result, during such operations those parts that you're working on redraw often and feel snappy and responsive, while areas further away may lag behind more.

• Faster blur for exporting and high quality on-screen rendering: Inkscape now uses an IIR (Infinite Impulse Response) filter for blurring with large radius. This greatly improves the speed of blur redraw at high zooms or in high-resolution export (or simply with very large blur radius). On the other hand, the results are an approximation to a true Gaussian blur, so a drawing may look slightly different from the mathematically precise blur (usually the differences are far from visible, though). This code is mainly based on: Recursive Gaussian Derivative Filters by L.J. van Vliet, I.T. Young and P.W. Verbeek (see the source code for more detailed references).

Exporting drawings with blur was particularly slow in 0.45; some files could take hours to export. Now this is fixed, in part by the faster algorithm mentioned above and in part by a bugfix in the export code. Now even the quite complex files with large blurs export at high resolution in at most a few minutes.

• Minor improvements have been made to gradient rendering performance.

• Dragging handles and nodes as well as dragging and transforming objects by mouse became more responsive, so that working in complex drawings and especially editing complex paths is noticeably easier. In particular, this fixes the annoying latency issue where a node or a handle could follow mouse cursor even after you release mouse button after a drag.

• Moving objects, nodes, and gradient handles by cursor keys as well as scaling and rotating objects from keyboard and zooming by keys are much more responsive when working with complex slow-rendering objects. Now, if you press and hold a key, your selection/zoom level will quickly jump to the final position instead of going through all the intermediate steps as before.

• Moving the cursor around in a file with large and complex paths has become much snappier and more responsive. Previously, in extreme cases Inkscape could freeze for seconds while catching up with the mouse cursor; such delays are now eliminated.

• Several improvements make canvas panning and scrolling smoother and more interactive in complex slow-rendering documents:

• When panning by the middle mouse button, Inkscape no longer attempts to redraw the canvas while your mouse button is pressed. Any redrawing only happens after you release the mouse. As a result, the newly revealed parts of the canvas are somewhat more "dirty" but the panning is smoother than before, with few if any "hiccups".

• Redrawing the newly exposed parts of the canvas after scrolling, especially diagonal scrolling, is now faster because only the exposed areas are redrawn; before, this often resulted in the entire screen being redrawn which was much slower.

• Previously, if you started panning with middle button while Inkscape is still redrawing screen in a complex drawing, panning sometimes completely failed or moved canvas just a little step. Now it is guaranteed to pan the canvas all the way from mouse-press point to mouse-release point in any case, even if sometimes it fails to show the intermediate positions.

• When pressing and holding Ctrl+arrows to scroll canvas, Inkscape normally accelerates scrolling so that each next scrolling step is bigger than the previous. Previously, in complex drawings this acceleration sometimes got interrupted, which made scrolling annoyingly bumpy and slow. Now this is fixed so that scrolling is smoothly accelerated even in a slow-rendering document.

• The default starting speed and acceleration of Ctrl+arrows scrolling are slightly increased. (They are both settable in Preferences.)

• Better responsiveness and more visual feedback in user interface:

• When you zoom, the zoom control on the right end of the statusbar now updates immediately, not after screen redraw as before.

• Many potentially slow commands (Save, Simplify, Combine, Break Apart and others) now display a busy cursor and flash a message in the statusbar (e.g. "Saving document...") while they work.

• The statusbar messages displayed while you're drawing a shape or a path in Pen tool do not lag behind the mouse movements.

• Combine and Convert to paths commands are now orders of magnitude faster when applied to a selection with hundreds or thousands of objects.

• The time it takes to snap to objects using the selector tool has been reduced dramatically, which is most noticeable for snapping to complex paths.

Tools

Paint Bucket tool

The new Paint Bucket tool works exactly as you would expect: click in any area bounded on all sides and it will fill it with color. Being a vector tool, however, Inkscape's Paint Bucket just creates a new path that "fills in" the area in which you clicked.

How it works

It is important to note that the tool is perceptual, not geometric. That is, when looking for the boundaries around the point you clicked, it takes for such boundaries any visible color changes. This means that filling will stop at gradients, blurs, and even the color boundaries in imported bitmaps, but will ignore any paths or other objects that are fully (or almost) transparent or for any other reason do not stand out from the background. In short, it will work exactly as if you were filling a rasterized version of your image in a bitmap editor like Photoshop or GIMP - but will give you a vector object to work with.

For example, now you can scan a pencil sketch, import the bitmap into Inkscape, and quickly fill all its cells with colors even without tracing the bitmap first. This is a very convenient and interactive way of digitizing your paper drawings, making the traditional bitmap tracing unnecessary in many cases.

Internally, the tool works by performing a bitmap-based flood fill on a rendered version of the visible canvas, then tracing the resulting fill using potrace and placing the traced path into the document.

It places the rendered path onto the current layer, so you can have a layer on top (for example, "Inks") and select the layer below ("Colors") and do the fills so that they always appear below the Inks.

The resolution of the bitmap image used to perform the trace is dependent upon your current zoom level -- the more zoomed in to an area that you are, the higher the resolution of the bitmap-based flood fill. So, if you are got a fill that is too imprecise, has rough corners, or don't go into small nooks and appendices where it is supposed to go, just undo, zoom in closer and repeat filling from the same point. Conversely, if the fill leaks out through a small gap, zoom out to make the gap less visible and fill again (or use the auto gap closing parameter, see below).

Style

Like all object-creating tools, the Paint Bucket may use the last-set style for the objects it creates (this is the default), or it can use its own fixed style. You can switch between these modes on this tool's page in Inkscape Preferences (Ctrl+Shift+P). As in all other tools, the style swatch on the far right of the Controls bar shows the style that will be used for the next fill object you create.

Controls

In the tool's Controls bar:

• Paint Bucket's perceptual fill can use either all visible colors or specific color channels. Using the Fill by drop-down list, you can restrict the fill algorithm to one the following channels:
  • Red
  • Green
  • Blue
  • Hue
  • Saturation
  • Lightness
  • Alpha

• The Threshold (in per cent units) controls how large must be color difference at a point (compared to the initial click point) to stop the fill. Zero tolerance means only the area of strictly the same color will be filled; the larger the tolerance, the easier it will be for the fill to leak into adjacent different-color areas. The default value is 10%.

• Using the Grow/shrink by parameter, you can control the amount of inset/outset to be applied to the created fill path. Setting a positive outset causes fill paths to be larger than the filled bitmap area (good for eliminating anti-aliasing errors), while setting a negative outset causes the path to be smaller. This works much the same as the Outset and Inset path commands, except it's done automatically after every fill.

• With the Close gaps parameter, you can make the Paint Bucket tool ignore any gaps in the area boundaries that would normally cause the fill to spill out of the desired area. There are four settings to auto gap:
  • None
  • Small (close gaps up to 2 pixels in size)
  • Medium (4 pixels)
  • Large (6 pixels)

Note that setting this parameter to other than None may slow down noticeably the filling of large areas.

Shortcuts

The tool's shortcuts are:

• Single click performs filling from the click point.

• Shift+click performs filling from the click point and then unions the resulting path with the selected path. This way, if your first attempt did not fill in all of the desired area, you can Shift+click the remaining corner to fill it in separately and combine the result with the result of the previous fill.

• Ctrl+click on an object simply changes that object's fill to the current fill color of the tool, and Shift+Ctrl+click changes the stroke to the current stroke color.

• Click and drag performs filling from all of the points that you pass while dragging (you will see your path visualized by a red line). From each point, the fill spreads to the neighbors with the colors similar to that point - in other words, it's like clicking with this tool at each point of the drag path and unioning the results. This lets you easily fill an area occupied by a gradient or blur - just drag from the darkest to the lightest points in the area you want to fill.

• Alt+click and drag works similarly to simple drag, except from each point of the drag path, the fill spreads to the neighbors (if any) with the colors similar to the initial point (the point where you started the drag). This lets you fill a series of similarly-colored yet separated areas (for example, multiple cells in a cartoon) by starting the drag in one of those areas, and alt+dragging the tool through all the other areas.

Tweak tool

The Tweak tool is an exciting new way to edit drawings which largely blurs the distinction between vector and raster editing. Instead of meticulously selecting some objects and then performing an action on the selection, you can now select all objects (or all objects you are interested in) and apply the Tweak tool's brush to smoothly and naturally change the shape or style of only those objects (or parts thereof) that the brush touches.

The area of the tool's action - its brush - is marked by an orange-colored circular outline that moves with your mouse cursor. However, that area actually has no sharp boundaries; the power of the tool's action falls off gradually, following a smooth bell-shaped profile. This makes the tool act softly and smoothly.

The tool will work on any number of selected objects; for example, you can select all (Ctrl+A) and "smear" your entire drawing by Push mode or paint it by Color Paint mode. You can also apply it to groups of objects; it will go into groups and act on individual objects inside groups. If you're trying to use it without anything selected, a message will appear in the statusbar reminding you to select some objects.

Width

The width of the tool's brush, in the range from 1 to 100, can be changed by the Width control in the tool's controls bar above the canvas. You can also change width by Left and Right arrow keys (same as in the Calligraphy tool) at any time (including during action) as well as Home and End. Also, as in Calligraphy tool, the visible width of the brush is independent of zoom; simply zooming in or out is often easier than adjusting the width if you want to cover a smaller or larger area of the drawing.

Force

The next control is Force which adjusts the power of the action, also in the range from 1 to 100. You can also change width by Up and Down arrow keys at any time (including during action).

If you have a pressure-sensitive tablet and your "Use pressure" button on the right-hand end of the controls bar is on, then the force will also depend on how hard you actually press your pen into your tablet, changing in the range from zero to whatever you set in the Force control. If all you have is a mouse, then the force will be constant but still settable by the Force control.

Path editing modes

The Tweak tool has a number of modes, selectable by toggle buttons in the tool's Controls bar and by keyboard shortcuts. Some of these modes change the shapes of paths while others affect the colors of objects. All these modes share the Width and Force controls but otherwise are quite different. Let's look at the path editing modes first.

Unlike the Node tool, to edit paths with the Tweak tool you don't need to worry about where the nodes of a path are and how to manipulate them. You just apply the tool's brush to any point, and the selected paths at that point will reshape smoothly and naturally - as if made of soft jelly - regardless of where its nodes lie. If applied to a shape or text object, the tool converts them to paths automatically.

While not very useful for technical drawings, tweaking paths will be indispensable for artistic uses of Inkscape - cartoons, drawings, sketches, anime, etc. This new functionality is somewhat similar to the tools such as "Pucker" and "Bloat" in the latest versions of Adobe Illustrator.

There are currently six path editing modes in the Tweak tool: Push, Shrink, Grow, Attract, Repel, and Roughen.

• This default mode of the tool, Push, simply displaces the part of the path under the cursor in the direction of the drag. The path behaves like soft jelly, bending and bulging smoothly and naturally. It's an easy way to produce various irregular, lifelike, handmade-looking shapes starting from something as simple as an ellipse or a calligraphic stroke. For parallel-stroke hatching (engraving) done in the Calligraphy tool, pushing is an easy way to bend, pinch, or curve the entire hatching uniformly.

• The Shrink and Grow are two opposite modes that move each point of a path in a direction perpendicular to the path's surface at the point, either inwards (Shrink) or outwards (Grow). This is similar to the Inset and Outset commands, except that the Tweak tool can act on a part of a path instead of the whole path.

For example, the visible lightness/darkness of an engraving hatching may not exactly correspond to your artistic intention. Also, the ends of Calligraphy pen strokes are often far from ideal - they may be too blunt or have unsightly bends or blobs. This is where the Tweak tool may help. Select all the strokes in a hatching pattern and apply a light Shrink action where you want the lines to become thinner (and the hatching to become lighter), up until total disappearance. If you press hard, shrinking works as an eraser, so you can easily clean the strokes' ends to make them thin, sharp, and uniform. Conversely, applying Grow makes strokes wider (i.e. the hatching becomes darker).

Of course, shrinking and growing are useful not only for calligraphic strokes. Same as with Push, with Shrink and Grow you can sculpt any path, spawning smooth treacle-like appendages with Grow and carving holes with Shrink. Unlike the "node sculpting" mode in the Node tool, however, this does not require adding new nodes to the shape.

• The Attract and Repel modes work by moving each affected point on a path towards (Attract) or from (Repel) the cursor point. In some cases this may look similar to Shrink and Grow, but the difference is that shrinking/growing moves paths perpendicularly to the path in each point, whereas attracting/repelling moves them to or from the cursor regardless of the path shape. These modes are similar to the Pinch effect in AI; you can use them for various central-symmetric distortions in parts of your paths.

• The Roughen mode does exactly this: roughens the edge of the path without changing its overall shape. Slight roughening simply makes the edge crooked and uneven; strong roughening tears and explodes the edge into random blobs and splotches. Note that this operation, especially with high Fidelity, adds a lot of nodes which increases the size of your SVG document and may slow down Inkscape considerably. In particular, pushing, shrinking, or growing of a roughened path becomes much slower and more difficult, so it's recommended to finalize the overall shape of a path first and roughen it, if necessary, only as the final step.

See the screenshot at [1] for a few examples of using the path editing modes of the Tweak tool.

Fidelity

Any tweaking of a path slightly distorts the entire path, including even those parts that you didn't touch. These distortions are similar to those that a Simplify command produces. The Fidelity value (also in the range from 1 to 100, default is 50) allows you to control the amount of these distortions. With a higher fidelity, the distortions are less noticeable, but the path may end up having a lot of nodes which inflates up the SVG size and slows down Inkscape.

The best value of Fidelity depends on the nature of your artwork. If you're sculpting an amorphous blob, you can do with low fidelity of about 20. If, however, you are pushing or inflating a text string (as a single path) and want the letters outside the distorted area to remain crisp and clean, you will need to raise fidelity to 80 or more.

Known problems

Known problems with the path editing modes in Tweak tool:

1. they don't work on open paths (an open path becomes closed if you tweak it);
2. they are rather slow;
3. they quickly eat memory; and
4. they are sometimes buggy - thin calligraphic strokes may suddenly disappear or change their shape drastically as you're shrinking or growing them.

For (4), it helps to increase Fidelity. Also, you can undo the bad change and try again with less pressure on the pen - if you do your thinning in several light touches instead of one heavy press, usually you will be able to get the desired result without the buggy behavior.

Also, sometimes after roughening, further tweaking of a path becomes impossible with this diagnostic:

 WARNING **: Shape error in ConvertToShape: directedEulerian(a) == false

All these problems stem from the livarot library that we use for geometric manipulation of paths. Fortunately, livarot is scheduled for replacement by lib2geom, a new library now in development, so hopefully these issues will be addressed then.

Color editing modes

The Color Paint and Color Jitter modes, unlike the path editing modes, change the colors of objects instead of their shapes. Yet they share enough common features with the path editing modes to be part of the same tool: These modes also use a circular soft-edged brush controlled by the Width and Force parameters on the Controls bar and affected by the pen pressure (if you have a pressure-sensitive tablet).

• Color Paint applies the style of the tool to the selected objects under the brush. The style of the tool is visible in the style swatch at the rightmost end of the tool's control bar; it can be changed by clicking on the color palette or by any other style assignment command, such as Fill and Stroke dialog. (Note: unlike all other tools, in Tweak tool in Color Paint mode you cannot assign style directly to selected objects; any style-setting command changes the tool's style instead.)

The fill from the tool's style applies to the fills of the painted objects, and the stroke applies to the strokes. If the tool's style has no fill or no stroke, it won't affect fills or strokes, correspondingly. For example, if you want to color the fills of objects blue but leave their strokes untouched, assign blue fill to the tool's style (just click blue on the palette) but set its stroke to None (middle-click the Stroke swatch in the statusbar). Similarly, master opacity in the tool's style affects master opacities of the touched objects (if the O channel is on, see below).

This mode allows you to literally paint over objects, shifting their colors towards the target style of the tool. For example, if you paint with yellow fill over a blue-filled object, the object will become greenish blue, then green, then yellowish green, and end up being exactly the yellow color you're painting with. This speed of this gradual transition depends on both Force parameter and pen pressure; also, objects touched by the periphery of the brush are less affected than those hit by the brush center. Overall, using this tool is very similar to a soft brush in a raster editor such as Gimp or Photoshop.

• Color Jitter mode does not apply any color, but instead jitters (randomizes) the colors of the objects it touches. The force of the action determines how strong is the randomization, i.e. how far the colors deviate from the original values. This mode does not use the tool's style.

Both modes work on flat fills and gradients; for gradients, the tool takes into account not only the position of the entire object with gradient, but also the position of each gradient stop relative to the brush. This means that, for example, you can change the blue color only in an object filled with blue-red gradient simply by painting over its blue end with a brush small enough to not touch the red. (Note that color tweaking does not create gradients on objects that used flat color before, but only adjusts existing gradients in the drawing.)

See the screenshot at [2] for a few examples of using the color editing modes of the Tweak tool.

Channels

Color Paint and Color Jitter honor the Channels control. This control comprises the four buttons: H, S, L, and O, which allow you to turn on and off the tool's action on the object's hue, saturation, lightness, and opacity, correspondingly. For example, if you want to raise the saturation of some part of your drawing without changing the hue, select some maximum-saturation color (e.g. pure red) and turn off all Channels buttons except S. Similarly, you can replace the hues without affecting saturation or lightness (only H pressed), or lighten/darken all colors without changing their hues and saturation (only L pressed). Pressing O allows you to apply the master opacity from the tool's style to the master opacity of objects (but not fill or stroke opacity).

Usage notes

Color painting with Tweak tool is similar, but not exactly analogous to bitmap painting. Even though the tool itself works as a soft brush, it still applies its color to vector objects, which behave as vector objects usually do. For example, if you want to change the tint of the face in your drawing, and if a hand in the drawing is part of the same object as the face, that hand will change its tint too even if it's located far from the point you are painting. (We foresee a "fracture" command in one of the next versions of Inkscape which will help you turn a monolithic object into a mosaic of small fragments that will be then easy to paint with Tweak tool.) Still, even with this limitation, color painting is a novel way of dealing with vector drawings which allows you to quickly and intuitively make adjustments which would be awkward and slow with traditional approach.

Drawings containing patterns or scatterings of small independent objects are best suited for color painting with Tweak tool. Examples include:

• freehand drawings with Calligraphy pen, consisting of many separate strokes;

• gradient meshes imported from Adobe Illustrator files (Inkscape renders these meshes as lattices of small polygons; while there's no direct support for gradient meshes in Inkscape yet, color painting on such lattices is almost as good);

• text converted to paths and with Break Apart command applied so that each letter is a separate path;

• patterns made with the Tile Clones command; note that you need to unset the fill and/or stroke on the original object and use the Color tab to assign some initial color to the clones - this will make them paintable with the Tweak tool without unlinking.

Moreover, color tweaking can be useful for compositions with a few objects or even for single objects. Unlike all other color selection methods, painting with the Tweak tool implements the color mixing metaphor which is much more familiar to traditional artists than RGB sliders or even the color wheel. For example, start with a rectagle of pure blue color; then, pick different colors by Color Paint and apply light touches with minimum Force and minimum pen pressure: add a little green, a little brown, a little yellow, etc. until you have the exact hue you need. Similarly, you can whiten or blacken any hue by admixing white or black.

You can also use color tweaking to add a tint, darken/lighten, saturate/desaturate, or color jitter your entire drawing. Just select all in all layers, zoom out, choose a large brush width so it covers all of the drawing, and apply a little color tweaking (with minimum Force) that will therefore affect all visible objects.

Keyboard shortcuts

• W, Shift+F2: switch to the Tweak tool

• Shift+P: switch to the Push mode

• Shift+S: switch to the Shrink mode

• Shift+G: switch to the Grow mode

• Shift+A: switch to the Attract mode

• Shift+E: switch to the Repel mode

• Shift+R: switch to the Roughen mode

• Shift+C: switch to the Color Paint mode

• Shift+J: switch to the Color Jitter mode

• Left, Right, Home, End: change width

• Up, Down: change force

• mouse drag: act on selected path in the current mode

• Ctrl+mouse drag: temporarily switch to Shrink (while Ctrl is down)

• Shift+Ctrl+mouse drag: temporarily switch to Grow (while Shift+Ctrl is down)

3D Box tool

Inkscape is a two-dimensional drawing tool. However, very often it is used to create drawings or objects that appear three-dimensional. The new 3D box tool helps you create such drawings by automating the most common operation: creating a box in a given 3D perspective. The tool automatically ensures that all sides of the box lie on the corresponding perspective lines. We're not going to compete with Blender - but even simple things can go a long way.

Currently in the 3D Box tool you can:

• Draw a 3D box by dragging on canvas; Shift+drag without releasing the mouse button to extrude in Z direction.

• Adjust any of its 3 dimensions by handles. The 4 handles on the front X/Y side resize it, the four ones on the back X/Y side expand/contract the box in Z direction. With Shift, the functions of handles on front and back sides are reversed. With Ctrl, the side-resizing handles snap to the coordinate axes or diagonals.

• Move a 3D box "in perspective" by dragging its center; without modifiers, movement occurs within the XY-plane (press Ctrl to constrain the movement to the directions of the coordinate axes or diagonals), with Shift the box moves parallel to the Z-axis.

• Adjust the vanishing points of a perspective by dragging them on the canvas (see below) or toggling their states; all boxes sharing this perspective are affected by a vanishing point move.

When several boxes are selected, all vanishing points of their associated perspectives are shown on the canvas. If vanishing points of different perspectives coincide, they are combined in a single "dragger". Moving this dragger moves all the vanishing points simultaneously and transforms the associated boxes accordingly. Note that some non-selected boxes may also be reshaped if their perspectives share the same vanishing point. Pressing Shift while moving the dragger can be used to only transform the selected boxes, separating their perspectives from the non-selected ones'. On the other hand, when a vanishing point being dragged comes close enough to another one, both snap together and are combined in a single dragger.

In SVG, a 3D box is represented as a group (svg:g) with a special extension attribute (in Inkscape's namespace); this group contains the 6 quadrilateral paths representing the sides of the box. Only the 3D box tool treats this object as a box; for all other tools it is just a group, so you can select any of the paths by Ctrl+click, apply any style to it, delete it, etc. You can of course transform the entire box or any face in it using Selector or Node tools.

Keyboard shortcuts

• X, Shift+F4: switch to the 3D box tool

• The various kinds of parentheses, namely [ ], ( ), { }, can be used to rotate infinite (i.e., parallel) perspective lines in X-, Y-, and Z-direction, respectively. Closing parentheses rotate clockwise and opening parentheses rotate counterclockwise. The angle of rotation is taken from the preferences. Pressing Alt reduces the amount of rotation to 1 screen pixel.

• When the 3D box tool is active, Shift+X, Shift+Y, and Shift+Z toggle perspective lines in the corresponding direction between "converging" and "parallel".

Gradient Tool

Selecting multiple stops

More than one gradient stop can be selected at a time. Shortcuts for working with multiple stop selections are generally modeled on the Node tool.

• Add a stop to the selected stops by Shift+click.
• Press Ctrl+A to select all stops in the selected objects.
• Shift+drag around stops to add them to selection.

Multiple selected stops:

• Can be moved together by mouse drag or by arrow keys. For example, creating a linear gradient, then press Ctrl+A to select all stops and use arrow keys to move the entire gradient as a whole.
• Can be deleted at the same time by pressing Del.

An always up-to-date description of the current handle selection is provided in the statusbar in the Gradient tool, including the number of selected handles (and the type of the single selected handle), as well as the total number of handles and selected objects.

Editing intermediate stops

Intermediate stops in gradients can be added, deleted, and edited on canvas (previously this was only possible in the Gradient Editor dialog).

• Stops can be added by double clicking or by Ctrl+Alt+Click on the gradient line. Also, you can drag-and-drop a color from the palette onto the gradient line to create a new stop with this color. Dropping a color on an existing stop changes the color of that stop.
• When two or more adjacent stops are selected, pressing Ins adds stops in the middles of all selected stop intervals.
• Intermediate stops can be mousedragged or moved by arrow keys along their gradient line, within the limits of the adjacent unselected stops (or end handles).

• Dragging with Ctrl moves the selected stops snapping them to 1/10 fractions of the available range.
• Dragging with Alt moves the selected stops depending on how close each one is to the stop being dragged, using a smooth bell-like curve similar to the node sculpting feature in Node tool. This makes it easy to approximate different gradient profiles; for example, if you have a two-stop gradient that you want to shape according to a curve profile, select both ends of the gradient, press Ins a few times to add a number of intermediate nodes, then Alt+drag a node in the middle to smoothly profile the gradient.

• Stops can also be moved by arrow keys with all the regular modifiers (Shift for 10x movement, Alt for pixel-size movement at the current zoom, Shift+Alt for 10 pixels movement at the current zoom).
• Stops can be deleted by Ctrl+Alt+Click on a stop or by the Del key for all the selected stop(s).

• When you delete an end stop, the nearest intermediate stop becomes the new end stop of the gradient (without moving - i.e., the gradient span becomes shorter).
• When you delete an end stop and there are no intermediate stops, the object will be painted with a solid fill taken from the color & opacity of the remaining stop.

• Pressing Ctrl+L with some intermediate stops selected attempts to simplify the selected portion of the gradient, removing those stops that can be removed without too much change in the way the gradient looks. In particular, new stops created by double-clicking or pressing Ins initially do not change the appearance of the gradient, so if you press Ctrl+L, all redundant stops that weren't moved or repainted since creation will be deleted.

Style of gradient stops

• When you have one of the gradient handles selected, its style (color and opacity) is reflected by the selected style indicator (left of the statusbar) and the Fill&Stroke dialog. Previously, opacity of a gradient handle was reflected as fill-opacity and stroke-opacity; now it is reflected as master opacity (the "O:" spinbutton in the selected style indicator, the "Master opacity" slider in Fill&Stroke). This makes it much easier to view and change opacity of gradient handles using only the selected style indicator in the statusbar.

• When multiple gradient stops are selected, the selected style indicator (in the statusbar) displays and controls the averaged color and opacity of the selected stops.

• When one or more gradient stops are selected, using the Copy command (Ctrl+C) copies to the clipboard the style (color and opacity) of the selected stop or the averaged style of several selected stops, not the entire object with gradient as before. This means you can now copy/paste style between stops: select the source stop(s), copy, select the destination stop(s), paste style (Ctrl+Shift+V). With several selected stops, this also allows you to easily average their colors and opacities by copying them and pasting the style back onto them. (After that, redundant gradient stops can be removed by simplification with Ctrl+L).
• If the selected object(s) have gradient in fill or stroke, the selected style indicator in the bottom-left corner of the editing window now displays a live gradient preview prefixed by R or L to indicate Radial or Linear gradients (instead of displaying "L Gradient" or "R Gradient" text labels as before). Also, this and other similar widget now use italic font face to indicate None and bold to indicate Unset.

Automatic duplication of gradients

When copy/pasting or duplicating an object with gradient, it now automatically gets a copy of the original gradient, so modifying it does not affect the source object's gradient anymore (before, you had to press the Duplicate button on the Gradient controls bar for this). The Duplicate button is therefore removed.

However, to accommodate the needs of users who have relied on sharing the same gradient definition across objects, this behavior can be optionally suppressed. The Prevent sharing of gradient definitions checkbox on the Misc tab of Inkscape Preferences is by default checked; if you uncheck it, Inkscape does not automatically copy gradient definitions for new objects, which means that copy/pasting, duplicating, pasting style, and explicit assignment of a gradient to an object via the Gradient tool controls results in a shared gradient definition, so that changing the colors or mid-stop positions of the gradient on one object (but not changing the coordinates of the end handles) affects all other objects that share the same definition.

Calligraphy tool: Engraver's Toolbox

Several new features were added to the Calligraphic pen to make Inkscape capable of the ancient art of line engraving. Traditional engraving is a very labour-intensive process, and while for a long time it was the only practical way of reproducing lifelike images in black-and-white print, about a century ago it was almost completely displaced by automatic halftone screens. However, line engravings have their characteristic charm, and there's no reason not to try to resurrect this art form with the help of Inkscape.

A brief visual guide to the new functionality can be seen on these screenshots:

http://inkscape.org/screenshots/gallery/inkscape-0.46-engraving1.png

http://inkscape.org/screenshots/gallery/inkscape-0.46-engraving2.png

Tracking a guide path with Ctrl

One of the most common operations in line engraving is hatching (or sometimes cross-hatching when several hatching grids cross): filling a space with many parallel straight or variously curved lines (usually of varying width to represent a gradual shading). You could try to achieve a similar effect with e.g. path interpolation (blending), but it is rather cumbersome and limited; manual drawing of hatch lines, on the other hand, is tedious and nearly impossible to do uniformly. Now Inkscape provides "assisted hatching" by tracking a guide path, allowing you to hatch quickly and uniformly and at the same time giving you sufficient manual control over the process.

Here's how to do this. First, select the guide path that you will track. It may be another calligraphic stroke, any path or shape, or even a letter of a text object. Then switch to Calligraphic pen, select the desired parameters (line width, angle, fixation etc.) and, before starting to draw, press Ctrl. You will see a gray track circle centered at your mouse pointer and touching the closest point on the selected guide path. (If you have no guide path selected, a statusbar message will tell you to select it.)

Now move your mouse close to the guide path, so that the track circle radius is equal to the desired spacing of your hatch pattern, and start drawing along the guide path. At that moment, the radius of the circle gets locked; now the circle slides along the guide path - and the actual stroke is drawn by the center of the tracking circle, not by your mouse point. As a result, you are getting a smooth stroke going parallel to the guide path and always at the same distance from it.

When the stroke is ready, release your mouse button (or lift your tablet pen) but do not let go of the Ctrl key because as long as you have it pressed, the tool remembers the hatch spacing you set when you started drawing. Now, you have just created a new stroke and, as usual with Inkscape tools, it gets selected instead of what was selected before. In our case, this means that the newly drawn stroke itself becomes the new guide path. Next, you can draw a second stroke along the first one, then a third one along the second, etc. Eventually you can fill any desired space with uniform hatching.

Alternatively, if you uncheck "Select new path" in the Calligraphy tool preferences, newly created strokes will not be selected, so your original guide path will be kept selected. In this mode, Inkscape will increase the tracking distance after each created stroke so that you can create uniformly spaced hatching by tracking a single guide path.

The attachment to the guide path is not absolute. If you stray your mouse pointer far enough from the guide path, you will be able to tear it off (the track circle turns from green to red) and move freely. This is intentional; this feature allows you, for example, to continue drawing a stroke past the end of a guide stroke, thus making your hatching cover a wider area than the initial guide path. Special care is taken to make such tearing off as smooth as possible and to suppress violent jerks, but this is not always possible; the general advice is to not try to hatch too fast. If jerking and unintended tearoffs still bother you, try increasing the Mass parameter.

Also, special code is in place to prevent flipovers - accidental jumps to the other side of the guide path. Brief flipovers are suppressed, but if you intentionally go over to the other side and stay there, eventually Inkscape will obey and your tracking stroke will also flip over to follow you.

Tracking a guide also allows some slight feedback by gradually changing the tracking distance in response to your drawing behavior. Thus, if you're consistently trying to draw closer or farther from the guide than the current tracking distance, the distance will correspondingly decrease or increase, so you will get a hatching that is slightly spacing in or out. (The effect is very slight, however, so as not to become a nuisance.) Also, note that since tracking follows the edge of the stroke, strokes of varying width (such as those tracing background, see below) will result in gradual bending of the hatching pattern as you proceed.

Tracing background by stroke width

There is a new toggle button on the Calligraphy tool's controls bar, Trace background. When on, the width of your pen depends on the lightness of the background under the stroke in each point, so that white translates into the minimum stoke width (1) and black translates to the maximum (which is set by the Width parameter). This can work alone or in combination with pressure sensitivity, depending on whether the "Use pressure" button is also toggled.

This feature allows you to not only hatch over an imported bitmap image or any drawing, but to do so automatically reproducing the highlights and shades of the background with your strokes becoming lighter and heavier as needed.

Misc features

• For consistency with other drawing tools, drawing with Shift in Calligraphy tool automatically unions the newly created stroke with whatever paths were selected (and selects the result). Thus, you can do a series of overlapping Shift+strokes to create one unioned path object instead of separate objects as before.

• To facilitate changing the Width parameter, the Home/End keys in Calligraphy tool switch you to the minimum (1) and maximum (100) width, correspondingly. (This is in addition to the Left/Right arrow keys that change Width by 1; remember also that you can press Alt+X, type any width, and press Enter.)

Selector

• A new selection mode is available: selecting by touch. In this mode, you draw a freehand path across the objects; when you release mouse button, all objects that are touched by this path get selected. This mode is very convenient in situations where you need to select objects so intermingled that selecting them by the rectangular rubberband is too difficult and so numerous that click-selecting them one by one is too tedious.

To activate selecting by touch, whenever you are drawing a rubberband rectangle, just press Alt to switch it to the touch mode. The rectangle will disappear and a red touch path will be shown instead. When dragging from an empty space, you can press Alt first and then start to drag to get the touch mode (note that your selection must be empty, otherwise Alt+dragging will move the selected objects instead). To start a touch selection from a point over an object, or to add to existing selection by touching, press Shift+Alt and then start to drag.

• Previously, the only way to switch selection from scale mode to rotate mode or back was to click on it, which was rather inconvenient when the selected object is in a group or under other objects. Now you can switch modes with keyboard as well by pressing Shift+S in Selector tool.

• Draging the scale handles with Alt now scales selection by an integer factor, i.e. up to 2, 3, 4, etc. times the original size or down to 1/2. 1/3, 1/4, etc. of the original size (in any of the two dimensions independently), as well as to -1/3, -1/2, -1, -2, -3, etc. This way you can, for example, mirror any object around one of the edges of its box. (This replaces the old and rarely used "slow" scaling mode with Alt.)

• Horizontal/vertical flipping: So far, flipping a selection made it flip within its bounding box, so that the latter remained fixed. In the move/scale mode of the selector tool, this behaviour remains unchanged. However, in rotate/shear mode flipping now happens about an (imaginary) vertical/horizontal axis through the rotation center. This is very handy, since the latter can be freely dragged around and snaps to all kinds of objects if desired.

Node tool

• If any of the nodes in the currently selected path is mouseovered, then horizontal/vertical flipping ('H' and 'V' keys), stepwise rotation ('[' and ']' keys) and scaling ('<' and '>' keys) now all use this specific node as center/axis. If there is no mouseovered node, the center of the bounding box is used instead (as is currently the case unconditionally). Nodes that are covered by one of their handles are also detected as mouseovered.

• As a long-requested feature, two entry fields are added to the toolbar which allow precise editing of the coordinates of selected nodes.

Rectangle Tool

• Ctrl+dragging now also allows the creation of rectangles with sides constrained to the golden ratio (approx. 1 : 1.618034), not only integer ratios.

Ellipse Tool

• It is now easy to create ellipses/circles passing through particular points. Normally, the starting and ending point of the mouse drag mark the corners of the bounding box. Now the Alt modifier can be used to enlarge the ellipse so that its circumference passes through these two points.

• Ctrl+Alt+drag is an exception from this rule. It creates a perfect circle whose diameter is defined by the starting and ending point of the drag.

Pen/Pencil Tools

These tools can now create single dots by Ctrl+click on the canvas. This creates a small circle filled with the current stroke color. The radius can be set in the Preferences of the respective tools (it is specified as a multiple of the current stroke width). Shift+Ctrl+click creates a dot twice the specified size, and Alt+Ctrl+click varies the size of the created dots randomly.

Dropper Tool

The shortcut 'D' is now used to toggle (not just switch to) the dropper tool - much like space is used to toggle the selector tool. That is, pressing 'D' a second time switches back to the tool used before.

SVG features

The tref element

Inkscape can now correctly open files with tref elements, and new tref elements can be created manually in the XML editor.

The actual character data contained in a text element can either be embedded directly, or it can be the character content of an element referenced by a tref.

While the textual content from the referenced element will be stripped of any markup before being used by the tref, the tref element can itself have the same attributes as a tspan. In fact, when rendered, it is as though the tref element is replaced by a tspan with the same attributes, and the referenced character data is embedded in that tspan.

The property xlink:href is used to refer to another element whose character data will be used. Any element can be referred to except an ancestor of the tref. When any of the text contained in the referred element changes, the tref will immediately be updated to display the new data.

Existing tref elements can be converted into tspan elements with Edit > Clone > Unlink Clone. If more than one tref is contained within a selection, all trefs will be converted into tspans. All attributes applied to the tref will be retained in the new tspan.

A tref element can be mixed with any other elements allowed to be contained by a text element.

The cloned character data rendered by the tref may not be edited, but any characters surrounding it can be changed. Styles cannot be applied to a subset of the cloned characters, but if all are selected, a style can be applied to the tref.

SVG filters

New filters supported

• The feBlend filter primitive gives us image blending modes, like in many image manipulation programs. These modes are screen, multiply, darken and lighten. There's a caveat, though: when blending an object against an semi-transparent background, the background will be accumulated twice, resulting in thicker objects under the bounding box of blended object. This is a limitation of current version of SVG format, not a bug in Inkscape.

• The feColorMatrix filter primitive applies a matrix transformation to colour of each rendered pixel. This allows for effects like turning object to grayscale, modifying colour saturation and changing colour hue.

• The feComposite filter primitive composites two images using one of the Porter-Duff blending modes (described in paper Compositing Digital Images by T. Porter and T. Duff, published in SIGGRAPH '84 Conference Proceedings, Association for Computing Machinery, Volume 18, Number 3, July 1984) or the aritmetic mode described in SVG standard. Porter-Duff blending modes are essentially logical operations between the images. For example, xor mode shows the areas, where either one of the objects is, but not the areas where both of the objects are. Arithmetic mode lets you specify coefficients k1-k4 for blending equation (result colour) = k1 * (first input colour) * (second input colour) + k2 * (first input colour) + k3 * (second input colour) + k4.

• The feConvolveMatrix lets you specify a Convolution to be applied on the image. Common effects created using convolution matrices are blur, sharpening, embossing and edge detection. There's a fairly good explanation and some example matrices at www.gamedev.net/reference/programming/features/imageproc/page2.asp. Note that while gaussian blur can be created using this filter primitive, the special gaussian blur primitive is faster and resolution-independent.

• Filter primitives feDiffuseLighting and feSpecularLighting create lighting maps for the object in input image. SVG doesn't have concept of third dimension, so these filters use alpha channel of input image as a height map: the more opaque given point in input image is, the nearer spectator it is considered to be. There exists an example for using these in Inkscape distribution, in share/examples/lighting_effects.svg or in SVN

• The feDisplacementMap filter primitive displaces the pixels in the first input using the second input as a displacement map, that shows from how far the pixel should come from. Classical examples are whirl and pinch effects, that can be found in most image manipulation programs and even in some screensavers, where this kind off effect is moving around screen, twisting desktop beneath it.

• The feFlood filter primitive fills its region with a given color and opacity. It can be used as an auxiliary tool, usualy in combination with other filter primitives, in order to facilitate some common color handling operations.

• The feImage filter primitive allows using external images as part of filtering chain. For example, one could use external image as a displacement map for feDisplacementMap or as a height map for lighting effects. Note that while SVG standard allows using other parts of the SVG file in this filter primitive, the current Inkscape implementation only allows external images.

• The feMerge filter primitive composites several temporary images inside the filter primitive to a single image. It uses normal alpha compositing for this. This is equivalent to using several feBlend primitives in 'normal' mode or several feComposite primitives in 'over' -mode.

• The feMorphology filter primitive provides erode and dilate effects, that are common in image manipulation programs. With erode, darker and more transparent areas spread to lighter and more opaque areas, whereas with dilate lighter and more opaque areas spread to darker and more transparent areas. For single-colour objects, this basically means, erode makes the object thinner and dilate makes it thicker.

• The feOffset filter primitive offsets the image by an user-defined amount. For example, this is useful for drop shadows, where the shadow is in a slightly different position than the actual object.

• The feTurbulence filter primitive renders Perlin noise. This kind of noise is useful in simulating several nature phenomena like clouds, fire and smoke and in generating complex textures like marble or granite.

See also wiki page Filter Effects for more info on filters in Inkscape in general.

Filters UI

• New dialog for creating and modifying filter effects (Object>Filter Effects...)
• The list at the left of the dialog displays all filters currently in the document.
  • New filters can be added with the Add button beneath the list
  • Right-clicking a filter for the pop-up menu allows duplicating or removing a filter.
  • Double-clicking a filter will apply it to all selected objects
  • A black dot is placed next to whatever filter is applied to the selected objects. If more than one filter is in use by selected objects, an unfilled dot is used instead.
• The second list, at the left of the dialog, displays the filter primitives that are contained within the currently-selected filter.
  • New primitives can be added by selecting the primitive type from the combo box beneath the list, and then pressing the Add button.
  • Right-clicking a primitive for the pop-up menu allows duplicating or removing a primitive.
  • Primitives can be rearranged by clicking and dragging any filter in the list.
  • When a filter is selected, the Settings group at the bottom of the dialog will change to display the attributes available for that primitive. Changing a setting results in an immediate update to the document.
  • The "in" and "in2" attributes for filters that support them are not shown in the Settings group. These input connections are displayed graphically in the list, under the Connections column.
    • Inputs for a particular filter are displayed as triangles. Depending on the primitive type, there may be one or two inputs (or more for Merge primitives.) Connections can be created by clicking on a triangle and dragging.
    • There are six standard input types that can be used for any primitive input; Source Graphic, Source Alpha, Background Image, Background Alpha, Fill Paint, and Stroke Paint. These are displayed vertically on the far right of the list. Click and drag from an input triangle to one of the standard inputs to connect them.
    • Primitives can also be connected to other primitives by clicking an input triangle and dragging upwards to another primitive. A primitive can only be connected to one higher up the list.
    • Single-clicking on an input triangle will unset it, returning it to the default. If it is on a Merge primitive, the input will be deleted.
    • Merge inputs have an empty input at the end. Dragging a connection from this input will add a new input to the primitive.

Live Path Effects (LPE)

Live path effects (not to be confused with extension effects or SVG filters) are a new way to non-destructively modify path and shape objects. Path effects affect the path data of an object but not its style. The original path is preserved and can be edited directly on-canvas, and the path effect applied to it will be updated live.

In this version, we include several path effects that are analogous to the corresponding extension effects (such as Path along Path effect and Pattern along Path that replaces the extension of the same name). The most important advantage of path effects is that they are, indeed, live - you can still edit the original path and the effect will update in real time (unlike the extension effects which were one-time one-way transformations). In the future, we plan to reimplement most if not all of path-changing extensions as live path effects.

Live path effects were developed by Johan Engelen as part of the GSoC 2007.