Using Inkscape effects wisely

Long Pipeline

The Filter Editor always includes the components of all the previously applied filters. If, for example, after applying the Bumps | Tinfoil filter, you also apply Shadows and Glows | Drop Shadow , the list of primitives grows by five entries. However, it's not apparent which filter primitives belong to Tinfoil and which belong to Drop Shadows . This complicates manual fine-tuning of what are already many combined primitives.

Each entry in the list of filters on the left of the editor window (call-out 5 in Figure 5) identifies a primitive filter combination used in the document. Their names can be odd: The most recent entry is based simply on an internal counter, whereas the others carry only the name of the last filter applied. Obviously, the combination of the first programmed base effect editor and the many base-effect bundled Filters didn't quite succeed.

You can change the name of the effect bundle with a double-click. A check mark indicates the currently activated filter. If you start the Filter Editor for an object to which no filters were applied, you can assign it one of the existing combination primitives by clicking the check box. It doesn't matter whether you assemble them using the presets from the Filters menu or with Add Effect (call-out 5).

The Filter Editor is thus useful both for subsequently assembling filters from the many filter primitives and creating your own combinations of effects. Other graphics programs don't have a tool of that kind.

You'll need a lot of practice before you can somewhat predict the combined effect of many complex filters. You should therefore experiment with the individual primitives separately at the beginning. In any case, you'll learn to appreciate how much effort and skill goes into the 220 filter presets that Inkscape provides.

Unfortunately, Inkscape takes a while to display a filter's application, mainly because the program gets stuck in many processes even at the Gaussian blur stage. The process becomes irritating when doing something as simple as dragging a selection rectangle redraws the image.

The currently too unstable developer version [4] does promise some improvements. The kernel changes are apparently taking up so much of the developer resources that major feature enhancements as in version 0.48 don't seem to be evident. However, because working with the faster renderer gets things done faster, the situation is understandable.

In stable version 0.48, it's often best to switch to display mode without effects using Ctrl+5. While working with Edit | Make a Bitmap Copy , it's also useful to create a rendered snapshot while hiding the actual object; you can do this by right-clicking Object Properties | Hide . Be sure not to set the File | Inkscape Preferences value for Resolution of Bitmap Copies too high, or the conversion can take several minutes.

Bending and Scribbling

Graphics created with older Inkscape versions often seemed simple and artless, because you had to set a control point on Bézier curves for each bend.

Frequent natural occurrences, like rough paper edges or the outline of bark or tree branches, couldn't easily be drawn in that manner. Fortunately, the graphic program's current version, apart from filters, provides numerous path effects that can be rendered into complex curves using your mouse and a few clicks.

The path effects are spread across two menu locations. Path | Path Effect Editor provides a series of Live Path Effects (LPEs; Figure 6). As with Filters, you can undo LPEs independently of the usual undo list, so you can easily revert to the object's original form. Additionally, the effect parameters can be altered and transferred to other objects with Path | Paste Path Effect .

Figure 6: Live Path Effects can be grafted onto existing paths and easily removed or changed. Unlike filters, they're not made for color filling but rather for edge determination.

The same does not apply to the script effects under Extensions | Modify Path , Extensions | Generate from Path , and Extensions | Render (Figure 7). Both types of path effects operate on paths only, as they're created with the help from the curve tool.

Figure 7: The 150 extensions include those for modifying paths or drawing patterns and graphs. Unlike the 13 LPEs, extensions are mostly destructive operations that can not be reverted to their original form after carrying out further drawing operations.

You can convert basic shapes like rectangles, ellipses, spirals, and even text with Path | Object to Path . The base object, however, gets lost in the process. That's why, especially with text, making a duplicate (right-click Object Properties | Hide ) is recommended. If you want the object again, click Object | Unhide All .

All objects colored in yellow in Figures 6 and 7 are based on the simple square at the upper left. The Bend effect bends an existing object using a control path that's created with the Node Tool . Envelope Deformation has four such control paths that work independently on each of the four sides of the rectangle. For complex paths, these functions ensure that you can make subtle adjustments to a basic motif with little effort.

You can get interesting results with Stitch Sub-Paths and Interpolate Sub-Paths . These path effects make it easy to create the cross-hatching and hair that are well-known to ink drawing, as the Inkscape documentation explains [5]. The Hatches (Rough) effect does not create carefully drawn lines but rather freehand scribbled ones.