Gimp/app/operations/layer-modes/gimpoperationreplace.c

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/* GIMP - The GNU Image Manipulation Program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* gimpoperationreplace.c
* Copyright (C) 2008 Michael Natterer <mitch@gimp.org>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <string.h>
#include <gegl-plugin.h>
#include "../operations-types.h"
app: change behavior of REPLACE mode for fully-transparent pixels When the result of compositing has an alpha value of 0, the corresponding color value is not mathematically defined. Currently, all out layer modes opt to preserve the destination's color value in this case. However, REPLACE mode is different enough to warrant a different behavior: Unlike the other layer modes, when the compositing opacity approaches 0 or 1, the output color value approaches the destination or source color values, respectively, regardless of the output alpha value. When the opacity doesn't approach 0 or 1, the output color value generally doesn't approach a limit as the output alpha value approaches 0, however, when both the destination and source alpha values are equal, the output color value is always a simple linear interpolation between the destination and source color values, according to the opacity. In other words, this means that it's reasonable to simply use the above linear interpolation for the output color value, whenever the output alpha value is 0. Since filters are commonly combined with the input using REPALCE mode with full opacity, this has the effect that filters may now modify the color values of fully-transparent pixels. This is generally desirable, IMO, especially for point filters. Indeed, painting with REPLACE mode (i.e., with tools that use gimp_paint_core_replace()) behaved excatly as described above, and had this property, before we switched gimp_paint_core_replace() to use the common compositing code; this created a discrepancy between painting and applying filters, which is now gone. A side effect of this change is that we can now turn gimp:replace into a NOP when the opacity is 100% and there's no mask, which avoids the compositing step when applying filters. We could previously only apply this optimization to PASS_THROUGH mode, which is a subclass of REPLACE mode. Note that the discussion above concerns the UNION composite mode, which is the only mode we currently use REPLACE in. We modify the rest of the composite modes to match the new behavior: CLIP_TO_BACKDROP always preserves the color values of the destionation, CLIP_TO_LAYER always preserves the color values of the source, and INTERSECTION always produces fully-zeroed pixels. (cherry picked from commit 27e8f452b34d4b4a570e8c9c3469b3b13e54dd61)
2019-02-14 07:31:29 -08:00
#include "gimp-layer-modes.h"
#include "gimpoperationreplace.h"
app: change behavior of REPLACE mode for fully-transparent pixels When the result of compositing has an alpha value of 0, the corresponding color value is not mathematically defined. Currently, all out layer modes opt to preserve the destination's color value in this case. However, REPLACE mode is different enough to warrant a different behavior: Unlike the other layer modes, when the compositing opacity approaches 0 or 1, the output color value approaches the destination or source color values, respectively, regardless of the output alpha value. When the opacity doesn't approach 0 or 1, the output color value generally doesn't approach a limit as the output alpha value approaches 0, however, when both the destination and source alpha values are equal, the output color value is always a simple linear interpolation between the destination and source color values, according to the opacity. In other words, this means that it's reasonable to simply use the above linear interpolation for the output color value, whenever the output alpha value is 0. Since filters are commonly combined with the input using REPALCE mode with full opacity, this has the effect that filters may now modify the color values of fully-transparent pixels. This is generally desirable, IMO, especially for point filters. Indeed, painting with REPLACE mode (i.e., with tools that use gimp_paint_core_replace()) behaved excatly as described above, and had this property, before we switched gimp_paint_core_replace() to use the common compositing code; this created a discrepancy between painting and applying filters, which is now gone. A side effect of this change is that we can now turn gimp:replace into a NOP when the opacity is 100% and there's no mask, which avoids the compositing step when applying filters. We could previously only apply this optimization to PASS_THROUGH mode, which is a subclass of REPLACE mode. Note that the discussion above concerns the UNION composite mode, which is the only mode we currently use REPLACE in. We modify the rest of the composite modes to match the new behavior: CLIP_TO_BACKDROP always preserves the color values of the destionation, CLIP_TO_LAYER always preserves the color values of the source, and INTERSECTION always produces fully-zeroed pixels. (cherry picked from commit 27e8f452b34d4b4a570e8c9c3469b3b13e54dd61)
2019-02-14 07:31:29 -08:00
static gboolean gimp_operation_replace_parent_process (GeglOperation *op,
GeglOperationContext *context,
const gchar *output_prop,
const GeglRectangle *result,
gint level);
app: layer mode code shuffling Commit 3635cf04ab69bafb76d7583da804f580f2d5fbf3 moved the special handling of bottom-layer compositing to GimpOperationLayerMode. This required giving the op more control over the process() function of its subclasses. As a temporary workaround, the commit bypassed the subclasses entirely, using "gimp:layer-mode" for all modes. This is the reckoning :) Add a process() virtual function to GimpOperationLayerMode, which its subclasses should override instead of GeglOperationPointComposer3's process() functions. Reinstate the subclasses (by returning the correct op in gimp_layer_mode_get_oepration()), and have them override this function. Improve the way gimp_operation_layer_mode_process() dispatches to the actual process function, to slightly lower its overhead and fix some thread-safety issues. Remove the "function" field of the layer-mode info array, and have gimp_layer_mode_get_function() return the GimpOperationLayerMode::process() function of the corresponding op's class (caching the result, to keep it cheap.) This reduces redundancy, allows us to make the ops' process() functions private, and simplifies SSE dispatching (only used by NORMAL mode, currently.) Move the blend and composite functions of the non-specialized layer modes to gimpoperationlayermode-{blend,composite}.[hc], respectively, to improve code organization. Move the SSE2 composite functions to a separate file, so that they can be built as part of libapplayermodes_sse2, allowing libapplayermodes to be built without SSE2 compiler flags. This allows building GIMP with SSE acceleration enabled, while running the resulting binary on a target with no SSE accelration. Add a "blend_function" field to the layer-mode info array, and use it to specify the blend function for the non-specialized modes. This replaces the separate switch() statement that we used previously. Remove the "affected_region" field of the layer-mode info array. We don't need it anymore, since we can go back to using GimpOperationLayerMode's virtual get_affected_region() function. Last but not least, a bunch of code cleanups and consistency adjustments.
2017-08-17 07:26:49 -07:00
static gboolean gimp_operation_replace_process (GeglOperation *op,
void *in,
void *layer,
void *mask,
void *out,
glong samples,
const GeglRectangle *roi,
gint level);
static GimpLayerCompositeRegion gimp_operation_replace_get_affected_region (GimpOperationLayerMode *layer_mode);
G_DEFINE_TYPE (GimpOperationReplace, gimp_operation_replace,
GIMP_TYPE_OPERATION_LAYER_MODE)
app: change behavior of REPLACE mode for fully-transparent pixels When the result of compositing has an alpha value of 0, the corresponding color value is not mathematically defined. Currently, all out layer modes opt to preserve the destination's color value in this case. However, REPLACE mode is different enough to warrant a different behavior: Unlike the other layer modes, when the compositing opacity approaches 0 or 1, the output color value approaches the destination or source color values, respectively, regardless of the output alpha value. When the opacity doesn't approach 0 or 1, the output color value generally doesn't approach a limit as the output alpha value approaches 0, however, when both the destination and source alpha values are equal, the output color value is always a simple linear interpolation between the destination and source color values, according to the opacity. In other words, this means that it's reasonable to simply use the above linear interpolation for the output color value, whenever the output alpha value is 0. Since filters are commonly combined with the input using REPALCE mode with full opacity, this has the effect that filters may now modify the color values of fully-transparent pixels. This is generally desirable, IMO, especially for point filters. Indeed, painting with REPLACE mode (i.e., with tools that use gimp_paint_core_replace()) behaved excatly as described above, and had this property, before we switched gimp_paint_core_replace() to use the common compositing code; this created a discrepancy between painting and applying filters, which is now gone. A side effect of this change is that we can now turn gimp:replace into a NOP when the opacity is 100% and there's no mask, which avoids the compositing step when applying filters. We could previously only apply this optimization to PASS_THROUGH mode, which is a subclass of REPLACE mode. Note that the discussion above concerns the UNION composite mode, which is the only mode we currently use REPLACE in. We modify the rest of the composite modes to match the new behavior: CLIP_TO_BACKDROP always preserves the color values of the destionation, CLIP_TO_LAYER always preserves the color values of the source, and INTERSECTION always produces fully-zeroed pixels. (cherry picked from commit 27e8f452b34d4b4a570e8c9c3469b3b13e54dd61)
2019-02-14 07:31:29 -08:00
#define parent_class gimp_operation_replace_parent_class
static void
gimp_operation_replace_class_init (GimpOperationReplaceClass *klass)
{
app: layer mode code shuffling Commit 3635cf04ab69bafb76d7583da804f580f2d5fbf3 moved the special handling of bottom-layer compositing to GimpOperationLayerMode. This required giving the op more control over the process() function of its subclasses. As a temporary workaround, the commit bypassed the subclasses entirely, using "gimp:layer-mode" for all modes. This is the reckoning :) Add a process() virtual function to GimpOperationLayerMode, which its subclasses should override instead of GeglOperationPointComposer3's process() functions. Reinstate the subclasses (by returning the correct op in gimp_layer_mode_get_oepration()), and have them override this function. Improve the way gimp_operation_layer_mode_process() dispatches to the actual process function, to slightly lower its overhead and fix some thread-safety issues. Remove the "function" field of the layer-mode info array, and have gimp_layer_mode_get_function() return the GimpOperationLayerMode::process() function of the corresponding op's class (caching the result, to keep it cheap.) This reduces redundancy, allows us to make the ops' process() functions private, and simplifies SSE dispatching (only used by NORMAL mode, currently.) Move the blend and composite functions of the non-specialized layer modes to gimpoperationlayermode-{blend,composite}.[hc], respectively, to improve code organization. Move the SSE2 composite functions to a separate file, so that they can be built as part of libapplayermodes_sse2, allowing libapplayermodes to be built without SSE2 compiler flags. This allows building GIMP with SSE acceleration enabled, while running the resulting binary on a target with no SSE accelration. Add a "blend_function" field to the layer-mode info array, and use it to specify the blend function for the non-specialized modes. This replaces the separate switch() statement that we used previously. Remove the "affected_region" field of the layer-mode info array. We don't need it anymore, since we can go back to using GimpOperationLayerMode's virtual get_affected_region() function. Last but not least, a bunch of code cleanups and consistency adjustments.
2017-08-17 07:26:49 -07:00
GeglOperationClass *operation_class = GEGL_OPERATION_CLASS (klass);
GimpOperationLayerModeClass *layer_mode_class = GIMP_OPERATION_LAYER_MODE_CLASS (klass);
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gegl_operation_class_set_keys (operation_class,
"name", "gimp:replace",
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"description", "GIMP replace mode operation",
NULL);
app: change behavior of REPLACE mode for fully-transparent pixels When the result of compositing has an alpha value of 0, the corresponding color value is not mathematically defined. Currently, all out layer modes opt to preserve the destination's color value in this case. However, REPLACE mode is different enough to warrant a different behavior: Unlike the other layer modes, when the compositing opacity approaches 0 or 1, the output color value approaches the destination or source color values, respectively, regardless of the output alpha value. When the opacity doesn't approach 0 or 1, the output color value generally doesn't approach a limit as the output alpha value approaches 0, however, when both the destination and source alpha values are equal, the output color value is always a simple linear interpolation between the destination and source color values, according to the opacity. In other words, this means that it's reasonable to simply use the above linear interpolation for the output color value, whenever the output alpha value is 0. Since filters are commonly combined with the input using REPALCE mode with full opacity, this has the effect that filters may now modify the color values of fully-transparent pixels. This is generally desirable, IMO, especially for point filters. Indeed, painting with REPLACE mode (i.e., with tools that use gimp_paint_core_replace()) behaved excatly as described above, and had this property, before we switched gimp_paint_core_replace() to use the common compositing code; this created a discrepancy between painting and applying filters, which is now gone. A side effect of this change is that we can now turn gimp:replace into a NOP when the opacity is 100% and there's no mask, which avoids the compositing step when applying filters. We could previously only apply this optimization to PASS_THROUGH mode, which is a subclass of REPLACE mode. Note that the discussion above concerns the UNION composite mode, which is the only mode we currently use REPLACE in. We modify the rest of the composite modes to match the new behavior: CLIP_TO_BACKDROP always preserves the color values of the destionation, CLIP_TO_LAYER always preserves the color values of the source, and INTERSECTION always produces fully-zeroed pixels. (cherry picked from commit 27e8f452b34d4b4a570e8c9c3469b3b13e54dd61)
2019-02-14 07:31:29 -08:00
operation_class->process = gimp_operation_replace_parent_process;
app: layer mode code shuffling Commit 3635cf04ab69bafb76d7583da804f580f2d5fbf3 moved the special handling of bottom-layer compositing to GimpOperationLayerMode. This required giving the op more control over the process() function of its subclasses. As a temporary workaround, the commit bypassed the subclasses entirely, using "gimp:layer-mode" for all modes. This is the reckoning :) Add a process() virtual function to GimpOperationLayerMode, which its subclasses should override instead of GeglOperationPointComposer3's process() functions. Reinstate the subclasses (by returning the correct op in gimp_layer_mode_get_oepration()), and have them override this function. Improve the way gimp_operation_layer_mode_process() dispatches to the actual process function, to slightly lower its overhead and fix some thread-safety issues. Remove the "function" field of the layer-mode info array, and have gimp_layer_mode_get_function() return the GimpOperationLayerMode::process() function of the corresponding op's class (caching the result, to keep it cheap.) This reduces redundancy, allows us to make the ops' process() functions private, and simplifies SSE dispatching (only used by NORMAL mode, currently.) Move the blend and composite functions of the non-specialized layer modes to gimpoperationlayermode-{blend,composite}.[hc], respectively, to improve code organization. Move the SSE2 composite functions to a separate file, so that they can be built as part of libapplayermodes_sse2, allowing libapplayermodes to be built without SSE2 compiler flags. This allows building GIMP with SSE acceleration enabled, while running the resulting binary on a target with no SSE accelration. Add a "blend_function" field to the layer-mode info array, and use it to specify the blend function for the non-specialized modes. This replaces the separate switch() statement that we used previously. Remove the "affected_region" field of the layer-mode info array. We don't need it anymore, since we can go back to using GimpOperationLayerMode's virtual get_affected_region() function. Last but not least, a bunch of code cleanups and consistency adjustments.
2017-08-17 07:26:49 -07:00
layer_mode_class->process = gimp_operation_replace_process;
layer_mode_class->get_affected_region = gimp_operation_replace_get_affected_region;
}
static void
gimp_operation_replace_init (GimpOperationReplace *self)
{
}
app: change behavior of REPLACE mode for fully-transparent pixels When the result of compositing has an alpha value of 0, the corresponding color value is not mathematically defined. Currently, all out layer modes opt to preserve the destination's color value in this case. However, REPLACE mode is different enough to warrant a different behavior: Unlike the other layer modes, when the compositing opacity approaches 0 or 1, the output color value approaches the destination or source color values, respectively, regardless of the output alpha value. When the opacity doesn't approach 0 or 1, the output color value generally doesn't approach a limit as the output alpha value approaches 0, however, when both the destination and source alpha values are equal, the output color value is always a simple linear interpolation between the destination and source color values, according to the opacity. In other words, this means that it's reasonable to simply use the above linear interpolation for the output color value, whenever the output alpha value is 0. Since filters are commonly combined with the input using REPALCE mode with full opacity, this has the effect that filters may now modify the color values of fully-transparent pixels. This is generally desirable, IMO, especially for point filters. Indeed, painting with REPLACE mode (i.e., with tools that use gimp_paint_core_replace()) behaved excatly as described above, and had this property, before we switched gimp_paint_core_replace() to use the common compositing code; this created a discrepancy between painting and applying filters, which is now gone. A side effect of this change is that we can now turn gimp:replace into a NOP when the opacity is 100% and there's no mask, which avoids the compositing step when applying filters. We could previously only apply this optimization to PASS_THROUGH mode, which is a subclass of REPLACE mode. Note that the discussion above concerns the UNION composite mode, which is the only mode we currently use REPLACE in. We modify the rest of the composite modes to match the new behavior: CLIP_TO_BACKDROP always preserves the color values of the destionation, CLIP_TO_LAYER always preserves the color values of the source, and INTERSECTION always produces fully-zeroed pixels. (cherry picked from commit 27e8f452b34d4b4a570e8c9c3469b3b13e54dd61)
2019-02-14 07:31:29 -08:00
static gboolean
gimp_operation_replace_parent_process (GeglOperation *op,
GeglOperationContext *context,
const gchar *output_prop,
const GeglRectangle *result,
gint level)
{
GimpOperationLayerMode *layer_mode = (gpointer) op;
/* if the layer's opacity is 100%, it has no mask, and its composite mode
* contains "aux" (the latter should always be the case in practice,
* currently,) we can just pass "aux" directly as output.
*/
if (layer_mode->opacity == 1.0 &&
! gegl_operation_context_get_object (context, "aux2") &&
(gimp_layer_mode_get_included_region (layer_mode->layer_mode,
layer_mode->real_composite_mode) &
GIMP_LAYER_COMPOSITE_REGION_SOURCE))
{
GObject *aux;
aux = gegl_operation_context_get_object (context, "aux");
gegl_operation_context_set_object (context, "output", aux);
return TRUE;
}
/* the opposite case, where the opacity is 0%, is handled by
* GimpOperationLayerMode.
*/
return GEGL_OPERATION_CLASS (parent_class)->process (op, context, output_prop,
result, level);
}
app: layer mode code shuffling Commit 3635cf04ab69bafb76d7583da804f580f2d5fbf3 moved the special handling of bottom-layer compositing to GimpOperationLayerMode. This required giving the op more control over the process() function of its subclasses. As a temporary workaround, the commit bypassed the subclasses entirely, using "gimp:layer-mode" for all modes. This is the reckoning :) Add a process() virtual function to GimpOperationLayerMode, which its subclasses should override instead of GeglOperationPointComposer3's process() functions. Reinstate the subclasses (by returning the correct op in gimp_layer_mode_get_oepration()), and have them override this function. Improve the way gimp_operation_layer_mode_process() dispatches to the actual process function, to slightly lower its overhead and fix some thread-safety issues. Remove the "function" field of the layer-mode info array, and have gimp_layer_mode_get_function() return the GimpOperationLayerMode::process() function of the corresponding op's class (caching the result, to keep it cheap.) This reduces redundancy, allows us to make the ops' process() functions private, and simplifies SSE dispatching (only used by NORMAL mode, currently.) Move the blend and composite functions of the non-specialized layer modes to gimpoperationlayermode-{blend,composite}.[hc], respectively, to improve code organization. Move the SSE2 composite functions to a separate file, so that they can be built as part of libapplayermodes_sse2, allowing libapplayermodes to be built without SSE2 compiler flags. This allows building GIMP with SSE acceleration enabled, while running the resulting binary on a target with no SSE accelration. Add a "blend_function" field to the layer-mode info array, and use it to specify the blend function for the non-specialized modes. This replaces the separate switch() statement that we used previously. Remove the "affected_region" field of the layer-mode info array. We don't need it anymore, since we can go back to using GimpOperationLayerMode's virtual get_affected_region() function. Last but not least, a bunch of code cleanups and consistency adjustments.
2017-08-17 07:26:49 -07:00
static gboolean
gimp_operation_replace_process (GeglOperation *op,
void *in_p,
void *layer_p,
void *mask_p,
void *out_p,
glong samples,
const GeglRectangle *roi,
gint level)
{
GimpOperationLayerMode *layer_mode = (gpointer) op;
gfloat *in = in_p;
gfloat *out = out_p;
gfloat *layer = layer_p;
gfloat *mask = mask_p;
gfloat opacity = layer_mode->opacity;
const gboolean has_mask = mask != NULL;
app: layer mode code shuffling Commit 3635cf04ab69bafb76d7583da804f580f2d5fbf3 moved the special handling of bottom-layer compositing to GimpOperationLayerMode. This required giving the op more control over the process() function of its subclasses. As a temporary workaround, the commit bypassed the subclasses entirely, using "gimp:layer-mode" for all modes. This is the reckoning :) Add a process() virtual function to GimpOperationLayerMode, which its subclasses should override instead of GeglOperationPointComposer3's process() functions. Reinstate the subclasses (by returning the correct op in gimp_layer_mode_get_oepration()), and have them override this function. Improve the way gimp_operation_layer_mode_process() dispatches to the actual process function, to slightly lower its overhead and fix some thread-safety issues. Remove the "function" field of the layer-mode info array, and have gimp_layer_mode_get_function() return the GimpOperationLayerMode::process() function of the corresponding op's class (caching the result, to keep it cheap.) This reduces redundancy, allows us to make the ops' process() functions private, and simplifies SSE dispatching (only used by NORMAL mode, currently.) Move the blend and composite functions of the non-specialized layer modes to gimpoperationlayermode-{blend,composite}.[hc], respectively, to improve code organization. Move the SSE2 composite functions to a separate file, so that they can be built as part of libapplayermodes_sse2, allowing libapplayermodes to be built without SSE2 compiler flags. This allows building GIMP with SSE acceleration enabled, while running the resulting binary on a target with no SSE accelration. Add a "blend_function" field to the layer-mode info array, and use it to specify the blend function for the non-specialized modes. This replaces the separate switch() statement that we used previously. Remove the "affected_region" field of the layer-mode info array. We don't need it anymore, since we can go back to using GimpOperationLayerMode's virtual get_affected_region() function. Last but not least, a bunch of code cleanups and consistency adjustments.
2017-08-17 07:26:49 -07:00
switch (layer_mode->real_composite_mode)
{
case GIMP_LAYER_COMPOSITE_UNION:
case GIMP_LAYER_COMPOSITE_AUTO:
while (samples--)
{
gfloat opacity_value = opacity;
gfloat new_alpha;
app: change behavior of REPLACE mode for fully-transparent pixels When the result of compositing has an alpha value of 0, the corresponding color value is not mathematically defined. Currently, all out layer modes opt to preserve the destination's color value in this case. However, REPLACE mode is different enough to warrant a different behavior: Unlike the other layer modes, when the compositing opacity approaches 0 or 1, the output color value approaches the destination or source color values, respectively, regardless of the output alpha value. When the opacity doesn't approach 0 or 1, the output color value generally doesn't approach a limit as the output alpha value approaches 0, however, when both the destination and source alpha values are equal, the output color value is always a simple linear interpolation between the destination and source color values, according to the opacity. In other words, this means that it's reasonable to simply use the above linear interpolation for the output color value, whenever the output alpha value is 0. Since filters are commonly combined with the input using REPALCE mode with full opacity, this has the effect that filters may now modify the color values of fully-transparent pixels. This is generally desirable, IMO, especially for point filters. Indeed, painting with REPLACE mode (i.e., with tools that use gimp_paint_core_replace()) behaved excatly as described above, and had this property, before we switched gimp_paint_core_replace() to use the common compositing code; this created a discrepancy between painting and applying filters, which is now gone. A side effect of this change is that we can now turn gimp:replace into a NOP when the opacity is 100% and there's no mask, which avoids the compositing step when applying filters. We could previously only apply this optimization to PASS_THROUGH mode, which is a subclass of REPLACE mode. Note that the discussion above concerns the UNION composite mode, which is the only mode we currently use REPLACE in. We modify the rest of the composite modes to match the new behavior: CLIP_TO_BACKDROP always preserves the color values of the destionation, CLIP_TO_LAYER always preserves the color values of the source, and INTERSECTION always produces fully-zeroed pixels. (cherry picked from commit 27e8f452b34d4b4a570e8c9c3469b3b13e54dd61)
2019-02-14 07:31:29 -08:00
gfloat ratio;
gint b;
if (has_mask)
opacity_value *= *mask;
new_alpha = (layer[ALPHA] - in[ALPHA]) * opacity_value + in[ALPHA];
2012-04-24 02:25:19 -07:00
app: change behavior of REPLACE mode for fully-transparent pixels When the result of compositing has an alpha value of 0, the corresponding color value is not mathematically defined. Currently, all out layer modes opt to preserve the destination's color value in this case. However, REPLACE mode is different enough to warrant a different behavior: Unlike the other layer modes, when the compositing opacity approaches 0 or 1, the output color value approaches the destination or source color values, respectively, regardless of the output alpha value. When the opacity doesn't approach 0 or 1, the output color value generally doesn't approach a limit as the output alpha value approaches 0, however, when both the destination and source alpha values are equal, the output color value is always a simple linear interpolation between the destination and source color values, according to the opacity. In other words, this means that it's reasonable to simply use the above linear interpolation for the output color value, whenever the output alpha value is 0. Since filters are commonly combined with the input using REPALCE mode with full opacity, this has the effect that filters may now modify the color values of fully-transparent pixels. This is generally desirable, IMO, especially for point filters. Indeed, painting with REPLACE mode (i.e., with tools that use gimp_paint_core_replace()) behaved excatly as described above, and had this property, before we switched gimp_paint_core_replace() to use the common compositing code; this created a discrepancy between painting and applying filters, which is now gone. A side effect of this change is that we can now turn gimp:replace into a NOP when the opacity is 100% and there's no mask, which avoids the compositing step when applying filters. We could previously only apply this optimization to PASS_THROUGH mode, which is a subclass of REPLACE mode. Note that the discussion above concerns the UNION composite mode, which is the only mode we currently use REPLACE in. We modify the rest of the composite modes to match the new behavior: CLIP_TO_BACKDROP always preserves the color values of the destionation, CLIP_TO_LAYER always preserves the color values of the source, and INTERSECTION always produces fully-zeroed pixels. (cherry picked from commit 27e8f452b34d4b4a570e8c9c3469b3b13e54dd61)
2019-02-14 07:31:29 -08:00
ratio = opacity_value;
if (new_alpha)
app: change behavior of REPLACE mode for fully-transparent pixels When the result of compositing has an alpha value of 0, the corresponding color value is not mathematically defined. Currently, all out layer modes opt to preserve the destination's color value in this case. However, REPLACE mode is different enough to warrant a different behavior: Unlike the other layer modes, when the compositing opacity approaches 0 or 1, the output color value approaches the destination or source color values, respectively, regardless of the output alpha value. When the opacity doesn't approach 0 or 1, the output color value generally doesn't approach a limit as the output alpha value approaches 0, however, when both the destination and source alpha values are equal, the output color value is always a simple linear interpolation between the destination and source color values, according to the opacity. In other words, this means that it's reasonable to simply use the above linear interpolation for the output color value, whenever the output alpha value is 0. Since filters are commonly combined with the input using REPALCE mode with full opacity, this has the effect that filters may now modify the color values of fully-transparent pixels. This is generally desirable, IMO, especially for point filters. Indeed, painting with REPLACE mode (i.e., with tools that use gimp_paint_core_replace()) behaved excatly as described above, and had this property, before we switched gimp_paint_core_replace() to use the common compositing code; this created a discrepancy between painting and applying filters, which is now gone. A side effect of this change is that we can now turn gimp:replace into a NOP when the opacity is 100% and there's no mask, which avoids the compositing step when applying filters. We could previously only apply this optimization to PASS_THROUGH mode, which is a subclass of REPLACE mode. Note that the discussion above concerns the UNION composite mode, which is the only mode we currently use REPLACE in. We modify the rest of the composite modes to match the new behavior: CLIP_TO_BACKDROP always preserves the color values of the destionation, CLIP_TO_LAYER always preserves the color values of the source, and INTERSECTION always produces fully-zeroed pixels. (cherry picked from commit 27e8f452b34d4b4a570e8c9c3469b3b13e54dd61)
2019-02-14 07:31:29 -08:00
ratio *= layer[ALPHA] / new_alpha;
for (b = RED; b < ALPHA; b++)
out[b] = (layer[b] - in[b]) * ratio + in[b];
out[ALPHA] = new_alpha;
in += 4;
layer += 4;
out += 4;
if (has_mask)
mask++;
2012-04-24 02:25:19 -07:00
}
break;
case GIMP_LAYER_COMPOSITE_CLIP_TO_BACKDROP:
while (samples--)
{
gfloat opacity_value = opacity;
gfloat new_alpha;
gint b;
if (has_mask)
opacity_value *= *mask;
new_alpha = in[ALPHA] * (1.0f - opacity_value);
for (b = RED; b < ALPHA; b++)
out[b] = in[b];
out[ALPHA] = new_alpha;
app: change behavior of REPLACE mode for fully-transparent pixels When the result of compositing has an alpha value of 0, the corresponding color value is not mathematically defined. Currently, all out layer modes opt to preserve the destination's color value in this case. However, REPLACE mode is different enough to warrant a different behavior: Unlike the other layer modes, when the compositing opacity approaches 0 or 1, the output color value approaches the destination or source color values, respectively, regardless of the output alpha value. When the opacity doesn't approach 0 or 1, the output color value generally doesn't approach a limit as the output alpha value approaches 0, however, when both the destination and source alpha values are equal, the output color value is always a simple linear interpolation between the destination and source color values, according to the opacity. In other words, this means that it's reasonable to simply use the above linear interpolation for the output color value, whenever the output alpha value is 0. Since filters are commonly combined with the input using REPALCE mode with full opacity, this has the effect that filters may now modify the color values of fully-transparent pixels. This is generally desirable, IMO, especially for point filters. Indeed, painting with REPLACE mode (i.e., with tools that use gimp_paint_core_replace()) behaved excatly as described above, and had this property, before we switched gimp_paint_core_replace() to use the common compositing code; this created a discrepancy between painting and applying filters, which is now gone. A side effect of this change is that we can now turn gimp:replace into a NOP when the opacity is 100% and there's no mask, which avoids the compositing step when applying filters. We could previously only apply this optimization to PASS_THROUGH mode, which is a subclass of REPLACE mode. Note that the discussion above concerns the UNION composite mode, which is the only mode we currently use REPLACE in. We modify the rest of the composite modes to match the new behavior: CLIP_TO_BACKDROP always preserves the color values of the destionation, CLIP_TO_LAYER always preserves the color values of the source, and INTERSECTION always produces fully-zeroed pixels. (cherry picked from commit 27e8f452b34d4b4a570e8c9c3469b3b13e54dd61)
2019-02-14 07:31:29 -08:00
in += 4;
out += 4;
if (has_mask)
mask++;
}
break;
case GIMP_LAYER_COMPOSITE_CLIP_TO_LAYER:
while (samples--)
{
gfloat opacity_value = opacity;
gfloat new_alpha;
gint b;
if (has_mask)
opacity_value *= *mask;
new_alpha = layer[ALPHA] * opacity_value;
app: change behavior of REPLACE mode for fully-transparent pixels When the result of compositing has an alpha value of 0, the corresponding color value is not mathematically defined. Currently, all out layer modes opt to preserve the destination's color value in this case. However, REPLACE mode is different enough to warrant a different behavior: Unlike the other layer modes, when the compositing opacity approaches 0 or 1, the output color value approaches the destination or source color values, respectively, regardless of the output alpha value. When the opacity doesn't approach 0 or 1, the output color value generally doesn't approach a limit as the output alpha value approaches 0, however, when both the destination and source alpha values are equal, the output color value is always a simple linear interpolation between the destination and source color values, according to the opacity. In other words, this means that it's reasonable to simply use the above linear interpolation for the output color value, whenever the output alpha value is 0. Since filters are commonly combined with the input using REPALCE mode with full opacity, this has the effect that filters may now modify the color values of fully-transparent pixels. This is generally desirable, IMO, especially for point filters. Indeed, painting with REPLACE mode (i.e., with tools that use gimp_paint_core_replace()) behaved excatly as described above, and had this property, before we switched gimp_paint_core_replace() to use the common compositing code; this created a discrepancy between painting and applying filters, which is now gone. A side effect of this change is that we can now turn gimp:replace into a NOP when the opacity is 100% and there's no mask, which avoids the compositing step when applying filters. We could previously only apply this optimization to PASS_THROUGH mode, which is a subclass of REPLACE mode. Note that the discussion above concerns the UNION composite mode, which is the only mode we currently use REPLACE in. We modify the rest of the composite modes to match the new behavior: CLIP_TO_BACKDROP always preserves the color values of the destionation, CLIP_TO_LAYER always preserves the color values of the source, and INTERSECTION always produces fully-zeroed pixels. (cherry picked from commit 27e8f452b34d4b4a570e8c9c3469b3b13e54dd61)
2019-02-14 07:31:29 -08:00
for (b = RED; b < ALPHA; b++)
out[b] = layer[b];
out[ALPHA] = new_alpha;
in += 4;
layer += 4;
out += 4;
if (has_mask)
mask++;
}
break;
2012-04-24 02:25:19 -07:00
case GIMP_LAYER_COMPOSITE_INTERSECTION:
app: change behavior of REPLACE mode for fully-transparent pixels When the result of compositing has an alpha value of 0, the corresponding color value is not mathematically defined. Currently, all out layer modes opt to preserve the destination's color value in this case. However, REPLACE mode is different enough to warrant a different behavior: Unlike the other layer modes, when the compositing opacity approaches 0 or 1, the output color value approaches the destination or source color values, respectively, regardless of the output alpha value. When the opacity doesn't approach 0 or 1, the output color value generally doesn't approach a limit as the output alpha value approaches 0, however, when both the destination and source alpha values are equal, the output color value is always a simple linear interpolation between the destination and source color values, according to the opacity. In other words, this means that it's reasonable to simply use the above linear interpolation for the output color value, whenever the output alpha value is 0. Since filters are commonly combined with the input using REPALCE mode with full opacity, this has the effect that filters may now modify the color values of fully-transparent pixels. This is generally desirable, IMO, especially for point filters. Indeed, painting with REPLACE mode (i.e., with tools that use gimp_paint_core_replace()) behaved excatly as described above, and had this property, before we switched gimp_paint_core_replace() to use the common compositing code; this created a discrepancy between painting and applying filters, which is now gone. A side effect of this change is that we can now turn gimp:replace into a NOP when the opacity is 100% and there's no mask, which avoids the compositing step when applying filters. We could previously only apply this optimization to PASS_THROUGH mode, which is a subclass of REPLACE mode. Note that the discussion above concerns the UNION composite mode, which is the only mode we currently use REPLACE in. We modify the rest of the composite modes to match the new behavior: CLIP_TO_BACKDROP always preserves the color values of the destionation, CLIP_TO_LAYER always preserves the color values of the source, and INTERSECTION always produces fully-zeroed pixels. (cherry picked from commit 27e8f452b34d4b4a570e8c9c3469b3b13e54dd61)
2019-02-14 07:31:29 -08:00
memset (out, 0, 4 * samples * sizeof (gfloat));
break;
}
return TRUE;
}
static GimpLayerCompositeRegion
gimp_operation_replace_get_affected_region (GimpOperationLayerMode *layer_mode)
{
GimpLayerCompositeRegion affected_region = GIMP_LAYER_COMPOSITE_REGION_INTERSECTION;
if (layer_mode->opacity != 0.0)
affected_region |= GIMP_LAYER_COMPOSITE_REGION_DESTINATION;
/* if opacity != 1.0, or we have a mask, then we also affect SOURCE, but this
* is considered the case anyway, so no need for special handling.
*/
return affected_region;
}