Takes a layer mode and a composite mode, and returns the region
included in the composition.
Use this function in GimpOperationLayerMode, instead of testing
for specific composite modes directly. Will also be used by
the next commit.
Indentation cleanup in gimp_layer_modes.h
... so that we can use it for other functions that involve
compositing regions (which we do in the next commit).
Rename gimp_operation_layer_mode_get_affect_mask() and
friends to _get_affected_region().
Commit 9d4084c82f skips conversion and
blending of (some) transparent source and destination pixels. When
`blend_out == blend_layer`, it banks on the fact that the alpha values
of `blend_out` would be the same as those of `blend_layer`, and hence
the same as those of `layer`; thing is, we only copy those values from
`layer` to `blend_layer` for the pixels that we *don't* skip, so this
assumption is just wrong :P This leaves us with bogus alpha values in
`blend_out` for the skipped pixels, when the above equality holds.
For composite modes that use the alpha values of `blend_op` (aka `comp`)
even for transparent input pixels (i.e., src-atop and src-in), this may
result in artifacts.
Fix this by simply initializing the alpha values of `blend_out` for
skipped pixels unconditionally.
... since that's the color space it actually works in.
Keep the legacy "Color (HSV)" mode's name as is, wrong as it is,
since, well, that's what it used to be called...
No need to do full back and forth RGB/HSV conversions.
Change the behavior such that fully desaturated values remain
desaturated, instead of saturating towards red.
Pixels whose source or destination alpha is zero are not blended, and
therefore do not need to be converted between the composite and blend
spaces (assuming a conversion is necessary to begin with.) When there
is a large enough segment of consecutive pixels that don't need
blending, split the conversion/blending process around it, so that
we don't convert too many unblended pixels unnecessarily.
For layers with lots of transparency, this can dramatically reduce
compositing time; for layers with no transparency, the added
overhead is rather negligible.
Merge mode lays the source layer on top of the destination, same as
normal mode, however, it assumes the source and destination are two
parts of an original whole, and are therefore mutually exclusive.
This is useful for blending cut & pasted content without artifacts,
or for replacing erased content in general.
Calculates the dot product of the two input colors, and uses that
as the value for all the output color's components. Basically,
a per-pixel mono mixer.
Useful for custom desaturation, component extraction, and crazier
stuff (bump mapping!)
Include erase mode in the menu for layers and general paint tools.
This makes the eraser tool somewhat unnecessary, but allows for
interesting use cases (e.g., airbrush eraser, etc.)
... possibly due to small win32 stack
Limit the number of samples processed in one go by gimp_composite_blend()
so that we don't overflow the stack when we alloca() buffers on it.
... and get rid of the dedicated op. This gives us support for all
the blend/composite options for this mode.
Rename COLOR_ERASE to COLOR_ERASE_LEGACY, with perceptual blending/
compositing and immutable everything, and add a new COLOR_ERASE
mode, defaulting to linear blending/compositing, with mutable
everything. Modify affected code.
These are more general, and more expensive, versions of the non-
subtractive compositing functions. They are used with modes that
specify the SUBTRACTIVE flag. This doesn't affect anything yet, but
the next commit ports color-erase mode to a blendfun.
Most modes only modify the *color* of overlapping dest/src regions,
however, erase and color-erase may also reduce their *alpha*, i.e.,
eliminate some of the overlapping content. Flag these modes with
the new SUBTRACTIVE flag, as they require more general compositing
code. The next commit adds the said code.
The mode group switching combo box is hard to discover, until we use the
default group instead of legacy group as default - it is better to make legacy
resemble the full old set to.
which returns an array of modes in the order they would appear in a
GimpLayerModeContext's UI (like tool options or the layers dialog),
without the separators.
Use it in context-commands.c and layers-commands.c instead of static
(and outdated) arrays for the actions that cycle through modes.
Instead, add a gimp_layer_mode_get_format() function, which takes
the layer mode, composite space, and blend space, and returns the
I/O format.
Currently, we always use the composite space format as the I/O
format. This simplifies gimp_composite_blend(), and gives us
composite-space support for the "special" layer mode ops for free.
Jehan