Comparison test between hardness and Force with .gbr and .vbr brushes

Submitted by jose americo gobbo (@americo_gobbo)

Link to original bug (#780950)

Odd effects using Hardness/Force sliders with raster brushes

I have made a series of the tests (making the figures to each part of these tests) to understand the reasons of the behavior differences between raster and parametric brushes around the slider Hardness and Force on Tool Options. All tests are made with Dynamics Off.

The brushes used on figures 1 to 7 are:

• 00-raster-256px_hardness=1.gbr
• 00-vbr-256px_hardness=1.vbr set-brushes-used-to-testing-hardness.tar.gz

Description of figures

• Figure 1 and Figure 2 > explains an emulation ideal to the raster brush with 256px shaped full opacity, using the Gaussian Blur dialog.
• Figure 3 > explains what is happening with raster brush when is applied the hardness via tool options slider.
• Figure 4 > explains in more details the way and the odd effect of the hardness slider on the raster brush.
• Figure 5 > explains how is working the raster brush with hardness slider... and is possible to see the odd effect on the mark brush. The test, in this case, was made with Force=0 and testing discrete values of Hardness range (top); and with Hardness=0 to testing discrete values of Force range (bottom).
• Figure 5a > explains as .vbr brush is working in the same and similar conditions of the previous figure (Figure 5).
• Figure 5b > is the illustration with the comparison of blurs on parametric and raster brush made and same way (is only a collage of Figure 5a [on top] and Figure 5 [on bottom].
• Figure 6 > is an illustration of the discrete variations of the Force x Hardness range applied to the parametric brush.
• Figure 7 > is an illustration of the discrete variations of the Force x Hardness range applied on raster brush.
• Figure 8 > illustration with a comparison between Parametric and Raster brushes with Force on default=50 and Force=100 (Tables 1 and 2). Table 3 is the dabs of different .vbr brushes with hardness 0, 25, 50, 75 and 100). The Table 3 of Figure 8 was made with dabs of the respective hardness value brush.