Add a canvas item group for previews, and a small preview infrastructure
to GimpDrawTool, and put the transform preview into the preview group,
which is below all guides, grid and layer boundaries.
which removes a lot of code from the transform tool, and reduces the
number of canvas items used for the transform grid from possibly
gazillions to one.
Removes a lot of code from the rectangle tool and fixes off-by-one
drawing problems because in image coordinates, lines can't be aligned
correctly with rectangles.
so wrong calls will run into precondition checks and warnings. This is
optional, but currently enabled, to reduce the risk of introducing
permanent new warnings for 2.8. See STRICT_TOOL_CHECKS in gimptool.h.
Add a transform matrix to GimpCanvasBoundary and get rid of the whole
BoundSeg transform code in boundary.c and gimpbrushcore.c, it was
impossible to get this right on that level. Also fix te extents of
GimpCanvasBoundary os it leaves no artifacts.
- add gimp_draw_tool_push_group()/pop_group() which manage a stack
of groups; all items automatically get added to the stack's top group
- use push_group()/pop_group() all over the place, which saves a lot
of code in most cases
- return GimpCanvasGroup not GimpCanvasItem pointers from
gimp_draw_tool_add_stroke_group() and fill_group()
Unrelated:
- add GipmCanvasGroup parameter to gimp_rectangle_tool_draw()
- put rect select's round corners into the stroke group to
avoid ugly overdrawing (the mis-alignment of arcs becomes
very visible now however, will fix that soon)
of the guide and sample point canvas items. They are too obscure to
additionally hide them, and these items are used rarely enough to
justify the additional parameter to the new() functions.
- Invalidate the proper area when an item gets added or removed.
- Draw the kept canvas items instead of calling a draw tool function.
- The draw tool now sets its item on the shell.
or when the draw tool is really stopped. This seems to get rid of any
remaining flickering and also reduces expose events. Also get rid of
the "is_drawn" state and API because they make no sense any longer.
