When a single blend-tool action adds and removes the same gradient
stop, restore the original gradient, rather than actually adding
and removing the stop, so that the affected midpoint returns to its
original state at the beginning of the action, rather than being
reset (and, consequently, so that the redo stack isn't lost.)
... from the undo stack
When a blend-tool edit action modifies the gradient, do a deep
comparison of the original gradient against the current gradient,
to test if anything changed, instead of just assuming that
something did change.
When one of the line widget's properties changes, only update the
blend tool filter if the property has an effect on the result. In
particular, don't update the filter when only the selection
changes.
Separate the handling of changes to the FG/BG color from the gradient
dirty signal handling, so that the gradient editor doesn't purge the
history in response. Additionally, correctly respond to such changes
whenever the gradient has segments that depend on the FG/BG colors,
even if the dependency is introduced after the gradient is selected.
Move the tool undo functionality of the blend tool to the editor,
and add support for undoing gradient edit operations. Each undo
step that affects the gradient holds, in addition to the line
endpoint poisitions, a copy of the gradient at the beginning of the
operation, as well as necessary information to allow the selection
to "follow" undo. When undoing the operation, the saved gradient
is copied back to the active gradient.
To avoid all kinds of complex scenarios, when the active gradient
changes, or when the gradient is modified externally (e.g., by the
(old) gradient editor), all undo steps that affect the gradient are
deleted from the history, while those that affect only the endpoint
positions are kept.
Allows setting the midpoint's position, blending function, and
coloring type.
The midpoint can be converted to a stop, and centered, through
editor buttons.
Allows setting the stop's position, and its left and right colors
and color types. A chain button can be used to modify the two
colors (and color types) together.
The stop can be deleted through an editor button.
To be used by the blend tool gradient editor to edit the gradient
endpoint/stop/midpoint properties corresponding to the selected
handle.
The GUI is currently empty; the following commits add its contents.
When a midpoint is double-clicked, convert it into a gradient stop
(i.e., split the corresponding segment at the midpoint,) by
responding to the line's handle-clicked signal.
Add a tentative_gradient member to GimpBlendTool, which, when set,
is displayed instead of the current gradient.
Use this to show a version of the gradient with the currently
selected stop deleted, upon receiving a prepare-to-remove-slider
signal, i.e., when the slider is about to be removed.
Add a boolean "modify active gradient" option to the blend tool.
when checked, the active gradient is modified in-place while edited.
When unchecked, the active gradient is copied to the internal
"custom" gradient upon editing, and the custom gradient becomes
subsequently active.
Show a hint when the option is checked, but the active gradient is
non-writable, and can't be edited directly.
This commit adds the new gimpblendtool-editor.[hc] files, which are
where the gradient-editing related functionality of the blend tool
is going to go.
