the angle arc and the small helper line were displayed on opposite
sides of the first point. Now they are on the same side, just like for
all other angles.
Add an offset_angle parameter to gimp_constrain_line(), which
offsets the radial lines by a given angle.
Add gimpdisplayshell-utils.[ch], with two new functions:
- gimp_display_shell_get_constrained_line_offset_angle():
Returns the offset angle to be passed to
gimp_constrain_line(), in order to constrain line angles in
display space, according to the shell's rotation angle and
flip mode.
- gimp_display_shell_constrain_line(): A convenience function
which calls gimp_constrain_line() with the said offset angle.
Use the new functions in all instances where we constrain line
angles, so that angles are constrained in display space, rather
than image space.
The only exception is GimpEditSelectionTool, which keeps
constraining angles in image space, since it's not entirely obvious
that we want to constrain angles of dragged layers/selections in
display space.
Rename gimp_tool_widget_snap_offsets() to set_snap_offsets(),
and add gimp_tool_widget_get_snap_offsets().
Also rename gimp_tool_widget_status() to set_status(), and
add new function and signal set_status_coords().
so widgets can return which handle was clicked. The values boolean
semantics stay the same so if(retval) gives the same result. This is
useful for the upcoming transform tool widgets.