Add a GimpTransformGridTool::matrix_to_info() virtual function,
which should extract the tool-specific transformation parameters
given a transformation matrix, and the old parameter set (which is
needed in some tools, to derive the parameters that aren't encoded
in the matrix, such as the pivot point). The transformation matrix
can be any combination of matrices calculated by the tool, and
their inverses. Subclasses should only implement this function if
every such matrix can be mapped back to transformation parameters.
This is currently the case for all the transform-grid tools, except
for the shear tool (since it only supports shearing along one of
the horizontal or the vertical directions, however, the combined
matrix may require shearing in both directions).
When a transform-grid tool implements this function, show a chain-
button between the two transform-direction radio-buttons in the
tool options. When the chain-button is linked, whenever the
transform corresponding to the active direction is modified, adjust
the transform corresponding to the non-active direction such that
the overall transform remains the same.
One notable workflow that this enables is transforming a layer
while adjusting a different area than its boundary, by first
defining the area while the transform-directions are linked, and
then transforming the area while the transform-directions are
unlinked.
In GimpTransformGridTool, allow performing simultaneous forward
(normal) and backward (corrective) transforms, by having each
transform direction operate on an independent set of parameters.
In other words, whereas the transform-grid tools previously had a
single transform, which could be applied either normally or
correctively using the "direction" tool-option, they now have two
independent transforms, one applied normally and the other
applied correctively, which are toggled using the "direction"
option. The overall transform is the combination of the backward
transform, followed by the forward transform.
Another way to think about it, is that the tool transforms a source
shape into a destination shape. The source shape is defined by the
backward transform, and the destination shape is defined by the
forward transform. Wherewas previously only one of these shapes
could be controlled (the other shape always being the item bounds),
it's now possible to control both shapes in a single transform.
The next commit will allow modifying both shapes simultaneously,
making this even more useful.
Note that since both transforms start off as the identity, using
only one of the transform directions has the same behavior as
before.
Add an undo_desc field to GimpTransformToolClass, which subclasses
should set to the tool's default undo description. Provide a
default implementation for the get_undo_desc() vfunc, which returns
(a copy of) undo_desc. This simplifies transform tools that have a
static undo descrption, as well as provides a fallback when a
detailed undo description can't be generated (not currently
relevant, but will be used in the next commit).
Get rid of GimpTransformGridTool::recalc_matrix() and
gimp_transform_grid_tool_recalc_matrix(), and have
GimpTransformGridTool and its subclasses use
GimpTransformTool::recalc_matrix() and
gimp_transform_tool_recalc_matrix() directly instead.
In order to break the GimpToolWidget::changed/
GimpTransformTool::recalc_matrix() loop, add a
GimpTransformGridTool::update_widget() vfunc, which subclasses
should override to update their tool-widget (instead of doing this
in ::recalc_matrix()), and ::widget_changed(), which is called when
the tool-widget changes (and which subclasses should override
instead of connecting to the tool-widget's "changed" signal
directly.) GimpTransformGridTool calls these functions as
necessary, instead of relying on extra parameters passed to
recalc_matrix().
Adapt all the direct and indirect subclasses of
GimpTransformGridTool to the change.
While most of our transform tools use an interactive transform
grid, and have similar behavior, the flip tool is an odd one out.
The new "auto straighten" function of the measure tool introduces
another tool that performs transformations, while not behaving like
the rest of the transform tools.
Factor out the parts of GimpTransformTool that handle user
interaction into GimpTransformGridTool (with corresponding
GimpTransformGridOptions, and GimpTransformGridToolUndo), and only
leave the basic transform functionality and options in
GimpTransformTool (and GimpTransformOptions).
Derive all the transform tools (and transform-tool base classes)
that previously derived from GimpTransformTool, from
GimpTransformGridTool. The one exception is GimpFlipTool, which
still derives from GimpTransformTool directly. The next commit
will derive GimpMeasureTool from GimpTransformTool as well.
Derive GimpUnifiedTransformTool, GimpPerspectiveTool, and
GimpHandleTransformTool from GimpGenericTransformTool, eliminating
their common logic.
Remove gimp_transform_matrix_handles(), which is no longer used.
In GimpCanvasTransformPreview, use the transform matrix to
determine if we're doing a perspective transform, rather than
relying on a separate property, so that we don't use the slow
perspective path unnecessarily.
Consequently, remove the does_perspective member of
GimpTransformTool, since it's no longer used.
Simply use g_object_bind_property() to connect the grid properties of
GimpTransformOoptions and GimpToolTransformGrid and remove all other
grid property setting code.
Remove all stock items added since 2.8, restore accidentially removed
ones, and rename the newly added GIMP_STOCK_* defines to GIMP_ICON_*.
(will move to having GIMP_ICON_* defines instead of magic hardcoded
strings for all icons).
Reorganize tool modes to be { ADD_TRANSFORM, MOVE, REMOVE }, where
ADD_TRANSFORM is the default and allows to add handles *and* transform
the image in one click-drag. MOVE moves handles without transforming
(shift) and REMOVE removes handles (control). Also improve cursors to
accurately show the result of a click.
Add new tool GimpHandleTransformTool which allows to freely place up
to 4 handles on the image, then move any one of them, which transforms
the image so that the remaining handles keep their position.
Did quite some cleanup on the code before pushing --Mitch
Ell