Holding shift while using the polygonal select tool now constrains the
line angle in 22.5 degree increments. This matches the behavior of the
line tool.
Previously, all keydown KeyEvents were accepted, causing parent widgets
not to receive them. With the addition of shortcut handling to keydown,
shortcuts were not called when the ImageEditor was focused.
Polygonal selection tool allows for the drawing of any arbitrary
polygonal shape. It tracks clicked points in a vector, upon double
clicking we finalize the polygon and generate the selection mask. The
user can press the escape key during selection to cancel.
The mask is generated as follows:
- First we calculate the size of the bounding rect needed to hold the
polygon
- We add 2 pixels to height/width to allow us a 1 pixel border, the
polygon will be centered in this bitmap
- Draw the polygon into the bitmap via Gfx::Painter, making sure to
connect final polygon point to the first to ensure an enclosed shape
- Generate a selection mask the size of the bitmap, with all pixels
initially selected
- Perform a flood fill from (0,0) which is guaranteed to be outside the
polygon
- For every pixel reached by the flood fill, we clear the selected pixel
from the selection mask
- Finally we merge the selection mask like other selection tools.
