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Introduced helper macros fooC to properly un-multiply pre-multiplied data

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* app/gegl/gimpoperationpointlayermode.c: Introduced helper macros
fooC to properly un-multiply pre-multiplied data without causing
NaNs. This fixes some compositing issues involving complete
transparency.

svn path=/trunk/; revision=27511
This commit is contained in:
Martin Nordholts
2008-11-01 09:52:58 +00:00
parent 891156945a
commit 657946b2a7
2 changed files with 29 additions and 19 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2008-11-01 Martin Nordholts <martinn@svn.gnome.org>
* app/gegl/gimpoperationpointlayermode.c: Introduced helper macros
fooC to properly un-multiply pre-multiplied data without causing
NaNs. This fixes some compositing issues involving complete
transparency.
2008-11-01 Martin Nordholts <martinn@svn.gnome.org>
* app/gegl/gimpoperationpointlayermode.c: Renamed fooC aliases to

41
app/gegl/gimpoperationpointlayermode.c
View File

@ -42,17 +42,20 @@
#define DISSOLVE_SEED 737893334
#define R RED
#define G GREEN
#define B BLUE
#define A ALPHA
#define inCa in[c]
#define inA in[A]
#define layCa lay[c]
#define layA lay[A]
#define outCa out[c]
#define outA out[A]
#define newCa new[c]
#define R (RED)
#define G (GREEN)
#define B (BLUE)
#define A (ALPHA)
#define inA (in[A])
#define inCa (in[c])
#define inC (in[A] ? in[c] / in[A] : 0.0)
#define layA (lay[A])
#define layCa (lay[c])
#define layC (lay[A] ? lay[c] / lay[A] : 0.0)
#define outCa (out[c])
#define outA (out[A])
#define outC (out[A] ? out[c] / out[A] : 0.0)
#define newCa (new[c])
#define EACH_CHANNEL(expr) \
for (c = RED; c < ALPHA; c++) \
@ -362,7 +365,7 @@ gimp_operation_point_layer_mode_process (GeglOperation *operation,
outCa = 0.0)
else
EACH_CHANNEL (
outCa = (inCa / inA) * outA);
outCa = inC * outA);
break;
case GIMP_ANTI_ERASE_MODE:
@ -373,7 +376,7 @@ gimp_operation_point_layer_mode_process (GeglOperation *operation,
outCa = 0.0)
else
EACH_CHANNEL (
outCa = inCa / inA * outA);
outCa = inC * outA);
break;
case GIMP_COLOR_ERASE_MODE:
@ -399,7 +402,7 @@ gimp_operation_point_layer_mode_process (GeglOperation *operation,
{
outA = 1.0;
EACH_CHANNEL (
outCa = layCa / layA);
outCa = layC);
}
else
{
@ -466,7 +469,7 @@ gimp_operation_point_layer_mode_process (GeglOperation *operation,
if (layCa * inA + inCa * layA >= layA * inA)
outCa = layA * inA + layCa * (1 - inA) + inCa * (1 - layA);
else
outCa = inCa * layA / (1 - layCa / layA) + layCa * (1 - inA) + inCa * (1 - layA));
outCa = inCa * layA / (1 - layC) + layCa * (1 - inA) + inCa * (1 - layA));
break;
case GIMP_BURN_MODE:
@ -492,11 +495,11 @@ gimp_operation_point_layer_mode_process (GeglOperation *operation,
/* XXX: Why is the result so different from legacy Soft Light? */
EACH_CHANNEL (
if (2 * layCa < layA)
outCa = inCa * (layA - (1 - inCa / inA) * (2 * layCa - layA)) + layCa * (1 - inA) + inCa * (1 - layA);
outCa = inCa * (layA - (1 - inC) * (2 * layCa - layA)) + layCa * (1 - inA) + inCa * (1 - layA);
else if (8 * inCa <= inA)
outCa = inCa * (layA - (1 - inCa / inA) * (2 * layCa - layA) * (3 - 8 * inCa / inA)) + layCa * (1 - inA) + inCa * (1 - layA);
outCa = inCa * (layA - (1 - inC) * (2 * layCa - layA) * (3 - 8 * inC)) + layCa * (1 - inA) + inCa * (1 - layA);
else
outCa = (inCa * layA + (sqrt (inCa / inA) * inA - inCa) * (2 * layCa - layA)) + layCa * (1 - inA) + inCa * (1 - layA));
outCa = (inCa * layA + (sqrt (inC) * inA - inCa) * (2 * layCa - layA)) + layCa * (1 - inA) + inCa * (1 - layA));
break;
case GIMP_ADDITION_MODE:
@ -576,7 +579,7 @@ gimp_operation_point_layer_mode_process (GeglOperation *operation,
* f(Sc, Dc) = Dc / Sc
*/
EACH_CHANNEL (
if (in[c] / lay[c] > in[A] / lay[A])
if (layA == 0.0 || inCa / layCa > inA / layA)
outCa = layA * inA + layCa * (1 - inA) + inCa * (1 - layA);
else
outCa = inCa * layA * layA / layCa + layCa * (1 - inA) + inCa * (1 - layA));