Like the change to op.Offset before this, clip.RRect and UniformRRect
is usually used with integer coordinates. Change to integer coordinates
to eliminate many useless conversions to float32.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
op.Offset is a convenience function most often used by layouts. Layouts
usually operate in integer coordinates, and the float32 version of op.Offset
needlessly force conversions from int to float32. This change makes op.Offset
take integer coordinates, to better match its intended use.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
When extracting headless.Window's content via screenshots,
it can be useful to keep reusing the same image for output,
as well as specify which area of the Window is to be
extracted.
The updated Screenshot method does this by using the supplied
image.
API change: users must pass an existing image to Window.Screenshot.
Signed-off-by: Pierre Curto <pierre.curto@gmail.com>
The op.Save and Load methods exist to support the need for
transformation, clip, pointer area state to behave as stacks. For
example, layout needs to apply an offset to its children but not
subsequent operations.
Before this change, op.Save and Load were used to save and restore the
state:
ops := new(op.Ops)
// Save state.
state := op.Save(ops)
// Apply offset.
op.Offset(...).Add(ops)
// Draw with offset applied.
draw(ops)
// Restore state.
state.Load()
A drawback with the op.Save mechanism is that there is no direct
connection between the state change and the saving and loading of state.
This causes confusion as to when a Save/Load is needed and who is
responsible for performing them, which leads to subtle bugs and over-use
of Save/Loads.
This change gets rid of the general state stack and replaces it with
per-state stacks. There is now a stack for transformation, clip, pointer
areas, and they can only be restored by the code pushing state to them.
The example above now becomes:
ops := new(op.Ops)
// Push offset to the transformation stack.
stack := op.Offset(...).Push(ops)
// Draw with offset applied.
draw(ops)
// Restore state.
stack.Pop()
For convenience, transformation also be Add'ed if the stack operation is
not required.
Simple state such as the current material no longer has a way to be
restored; it is assumed the client of a PaintOp adds their desired
material operation before it.
API change: replace op.Save/Load with explicit Push/Pop scopes for
op.TransformOps, pointer.AreaOps, clip.Ops.
To ease porting, this change retains a version of op.Save/Load that
saves and restores the transformation and clip stacks. It also retains
an Add method for clip.Op.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
GPU contexts can hold on to a significant amount of resources. Clean
them up immediately instead of at test cleanup.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Elias Naur