Bitmap Tracer
Chapter 1.
Introduction
The Xara Bitmap Tracer is a utility that generates a collage of vector shapes to represent a bitmap
image. The main use of bitmap tracers is to convert line drawings, pencil sketches or simple logos
into resolution-independent vector groups, allowing them to be scaled without loss in quality, or
causing pixelation. A secondary use is to produce visual effects on photos by tracing them in a
particular way that distorts its original look.
The Xara Bitmap Tracer technology dates back to 1995 and was included in the original CorelXara.
It is still the quickest tracer available, and is also the most memory efficient when producing traces.
demonstrate examples of settings for accomplishing various tasks such as tracing line drawings etc.
Chapter 4 will briefly compare the results of the Xara Tracer to other tracers available on the
market.
Chapter 2.
Bitmap tracer controls
This section will discuss the Bitmap Tracer’s controls and how they affect the final traced image.
Note: In general, high resolution bitmap images produce better traced results due to the increased
amount of information available, but can also produce more shapes and result in more CPU
resources to manipulate afterwards.
The Bitmap Tracer can be accessed by selecting a bitmap image such as a photo, selecting the
Utilities menu option, and selecting Bitmap Tracer.
2.1.
Tracer control panel
The Bitmap Tracer control panel is shown in Figure 2.1. The highlighted drop-down box allows any
bitmap in the Bitmap gallery to be traced, should the currently selected one not be desired.
2.2.
Image type choice
The image type list below the highlighted option in Figure 2.1 allows the selection of the general
form of output that the tracer should produce. The choice of image type selected should reflect the
number of colours present in the image; the choices alter the controls in the dialogue to reflect the
2.3.
Passes
The Passes setting determines how many parses of the image are made to complete the trace.
Each pass over the image produces more shape layers. This option is only available for the
typically at least 4 passes are required for the highest quality results.
2.4.
Remove noise
The Remove noise setting effectively determines how blurred the image is made in the
background before the trace starts. This option, when used sparingly, can be useful for smoothing
2.5.
Minimum area
The Minimum area setting determines the threshold size of detail to be traced. The image below
shows circles increasing in size from the centre of the image. Low values of this setting allow the
smaller circles to be traced, whereas large values only allow the larger circles to be traced, as
2.6.
Color tolerance
The Color tolerance settings determine how sensitive the trace is to the colour regions of an
have no effect as there are only two colours: black and white. The Greyscale and Limited color
types allow control over the Final color tolerance only, whereas the Photographic type allows
control over both Initial and Final color tolerance for the successive image passes that are
possible with this type. Large values of either Initial or Final color tolerance settings make the
tracer more tolerant to colour differences, so fewer are displayed. Conversely, lower values make
the tracer less tolerant to differences in colour regions in the image, and so more are picked up in
the trace, making more detailed images.
For the Photographic image type, multiple passes can be made, and each pass is less tolerant to
colour than the last—more colours are successively built into the final traced image. The best
image quality is produced if initially the tolerance is low, so general shapes are picked out, and the
final tolerance is high, so in the latter tracer passes, the smaller colour-differences are picked out.
2.7.
Accuracy
The Accuracy setting determines how accurately the traced shapes match regions of similar colour
in the original bitmap. Figure 2.7 highlights this; higher Accuracy values result in more shapes and
points, and more CPU intensive traces.
2.8.
Smoothing
The Smoothing setting refers to edge smoothing. It determines how many control points make up
the individual shapes produced. High Smoothing values have very few points and so may not
accurately match the original bitmap image shapes; whereas low Smoothing fits many control
points for a better match. Too many control points can generate overly complex results that require
Chapter 3.
Examples of tracer use
1.
Producing vector versions of line drawings, sketches or simple logos to allow scaling without
image degradation;
2.
Creating visual effects on full colour photo traces.
Examples of settings required to achieve these categories of use will be discussed in their own
subsections below.
3.1.
Tracing line art
Pencil sketches that are scanned into a computer end up as a bitmap. Scaling the bitmap up in size
(or zooming in) results in pixelation and loss of quality. This can be resolved by converting the
bitmap line sketch from a pixelated bitmap to a resolution independent vector compilation by using
the Bitmap Tracer.
The following is a walkthrough of such a process that has taken inspiration from Guest tutorial 49 in
the Xara Xone.
A scanned line sketch is going to be traced and filled as shown in Figure 3.1. The original bitmap
scan is shown in the top left image in the figure, and is traced using the settings shown in Figure
3.2. It is a greyscale image, and thus the greyscale colour setting is used.
Once the image is traced and inserted into the document, any gaps in line spaces are manually
closed, and the closed shapes filled.
3.2.
Tracing simple logos
Simple logos containing a few flat colours are also ideal for tracing. Using the settings shown in
Figure 3.3, it is possible to reproduce a vector trace of the original bitmap logo. With so few colours
in the logo, the limited colour setting is chosen.
3.3.
Creating visual effects
Visual effects on photos can be created by tracing with settings that do not overly accurately
reproduce the image. There is a large array of setting values for a given photo that can be chosen
Chapter 4.
Tracer comparisons
This section will briefly discuss the relative advantages and disadvantages of the various common
tracers available.
4.1.
Xara Bitmap Tracer
The Xara bitmap tracer is unmatched in speed, efficiency of memory usage, and accuracy of full
colour photo traces—in particular for regions containing smooth colour gradients (owing to its
collage like object placement). However, its ability to reproduce smooth, clean edges for line
drawings or simple logos is significantly bettered by all other tracers.
4.2.
Adobe Illustrator’s Live Trace
Illustrator’s Live Trace is second best of the tracers discussed in this chapter at producing smooth
clean edges when tracing line drawings and simple logos. It produces fairly accurate full colour
photo traces, but shows obvious colour stepping in parts of images containing colour gradients. Its
memory efficiency and
speed are quite poor; large amounts of memory are required for more complex traces, and it can
take many, many times longer to trace than Xara’s Bitmap Tracer.
4.3.
Corel Draw X3 PowerTRACE
PowerTRACE was released with CorelDraw X3 and shares similarities with Adobe Illustrator’s Live
Trace (section 4.2). It produces good results when tracing simple line drawings or logos, but when
subjected to tracing full colour photos, the output is considerably poorer than either Live Trace or
Xara’s Bitmap Tracer—even for photos not containing colour gradients. Its speed is faster than
Illustrator’s Live Trace, but considerably slower than Xara’s Bitmap Tracer
4.4.
Vector Magic
Vector Magic produces the most accurate trace of line drawings and simple logos of the Tracers
discussed in this chapter. Full colour, complex photos are traced with quality that is superior to
PowerTRACE’s output, but not as good as Illustrator’s or Xara’s (some details are lost). Colour
gradients are very well traced however, and are of higher quality than Live Trace or PowerTRACE.
Its speed is comparable with Corel’s PowerTRACE (section 4.3). However, Vector Magic charges
$300 for their download software (as of Feb 12th 2009).
Chapter 5.
Final Notes
Xhris
Contents
Chapter 1. Introduction
Chapter 2. Bitmap tracer controls
2.1. Tracer control panel
2.2. Image type choice
2.3. Passes
2.4. Remove noise
2.5. Minimum area
2.6. Color tolerance
2.7. Accuracy
2.8. Smoothing
Chapter 3. Examples of tracer use
3.1. Tracing line art
3.2. Tracing simple logos
Chapter 4. Tracer comparison
4.1. Xara Bitmap Tracer
4.4. Vector Magic
Contents
Chapter 1. Introduction
Chapter 2. Bitmap tracer controls
2.1. Tracer control panel
2.2. Image type choice
2.3. Passes
2.4. Remove noise
2.5. Minimum area
2.6. Color tolerance
2.7. Accuracy
2.8. Smoothing
Chapter 3. Examples of tracer use
3.1. Tracing line art
3.2. Tracing simple logos
Chapter 4. Tracer comparison
4.1. Xara Bitmap Tracer
4.4. Vector Magic
Contents
Chapter 1. Introduction
Chapter 2. Bitmap tracer controls
2.1. Tracer control panel
2.2. Image type choice
2.3. Passes
2.4. Remove noise
2.5. Minimum area
2.6. Color tolerance
2.7. Accuracy
2.8. Smoothing
Chapter 3. Examples of tracer use
3.1. Tracing line art
3.2. Tracing simple logos
Chapter 4. Tracer comparison
4.1. Xara Bitmap Tracer
4.4. Vector Magic
Contents
Chapter 1. Introduction
Chapter 2. Bitmap tracer controls
2.1. Tracer control panel
2.2. Image type choice
2.3. Passes
2.4. Remove noise
2.5. Minimum area
2.6. Color tolerance
2.7. Accuracy
2.8. Smoothing
Chapter 3. Examples of tracer use
3.1. Tracing line art
3.2. Tracing simple logos
Chapter 4. Tracer comparison
4.1. Xara Bitmap Tracer
4.4. Vector Magic
Contents
Chapter 1. Introduction
Chapter 2. Bitmap tracer controls
2.1. Tracer control panel
2.2. Image type choice
2.3. Passes
2.4. Remove noise
2.5. Minimum area
2.6. Color tolerance
2.7. Accuracy
2.8. Smoothing
Chapter 3. Examples of tracer use
3.1. Tracing line art
3.2. Tracing simple logos
Chapter 4. Tracer comparison
4.1. Xara Bitmap Tracer
4.4. Vector Magic
Contents
Chapter 1. Introduction
Chapter 2. Bitmap tracer controls
2.1. Tracer control panel
2.2. Image type choice
2.3. Passes
2.4. Remove noise
2.5. Minimum area
2.6. Color tolerance
2.7. Accuracy
2.8. Smoothing
Chapter 3. Examples of tracer use
3.1. Tracing line art
3.2. Tracing simple logos
Chapter 4. Tracer comparison
4.1. Xara Bitmap Tracer
4.4. Vector Magic
Contents
Chapter 1. Introduction
Chapter 2. Bitmap tracer controls
2.1. Tracer control panel
2.2. Image type choice
2.3. Passes
2.4. Remove noise
2.5. Minimum area
2.6. Color tolerance
2.7. Accuracy
2.8. Smoothing
Chapter 3. Examples of tracer use
3.1. Tracing line art
3.2. Tracing simple logos
Chapter 4. Tracer comparison
4.1. Xara Bitmap Tracer
4.4. Vector Magic
