more correct implementation of B_OP_COPY, in that it blends against the current low color (as seen in text rendering on BeOS), of course this extends to anti-aliased lines on Haiku

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@12559 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/servers/app/drawing/Painter/drawing_modes/DrawingMode.h

@@ -13,8 +13,9 @@ class PatternHandler;
 
 // BLEND
 //
-// this macro assumes source alpha in range 0..255 and
+// This macro assumes source alpha in range 0..255 and
-// ignores dest alpha (is assumed to equal 255)
+// ignores dest alpha (is assumed to equal 255).
+// TODO: We need the assignment of alpha only when drawing into bitmaps!
 #define BLEND(d1, d2, d3, da, s1, s2, s3, a) \
 { \
 	(d1) = (((((s1) - (d1)) * (a)) + ((d1) << 8)) >> 8); \
@@ -23,10 +24,26 @@ class PatternHandler;
 	(da) = max_c((da), (a)); \
 }
 
+// BLEND_FROM
+//
+// This macro assumes source alpha in range 0..255 and
+// ignores dest alpha (is assumed to equal 255).
+// It uses two colors for the blending (f and s) and writes
+// the result into a third color (d).
+// TODO: We need the assignment of alpha only when drawing into bitmaps!
+#define BLEND_FROM(d1, d2, d3, da, f1, f2, f3, s1, s2, s3, a) \
+{ \
+	(d1) = (((((s1) - (f1)) * (a)) + ((f1) << 8)) >> 8); \
+	(d2) = (((((s2) - (f2)) * (a)) + ((f2) << 8)) >> 8); \
+	(d3) = (((((s3) - (f3)) * (a)) + ((f3) << 8)) >> 8); \
+	(da) = max_c((da), (a)); \
+}
+
 // BLEND16
 //
-// this macro assumes source alpha in range 0..65025 and
+// This macro assumes source alpha in range 0..65025 and
-// ignores dest alpha (is assumed to equal 255)
+// ignores dest alpha (is assumed to equal 255).
+// TODO: We need the assignment of alpha only when drawing into bitmaps!
 #define BLEND16(d1, d2, d3, da, s1, s2, s3, a) \
 { \
 	(d1) = (((((s1) - (d1)) * (a)) + ((d1) << 16)) >> 16); \
@@ -37,8 +54,8 @@ class PatternHandler;
 
 // BLEND_COMPOSITE
 //
-// this macro assumes source alpha in range 0..255 and
+// This macro assumes source alpha in range 0..255 and
-// composes the source color over a possibly semi-transparent background
+// composes the source color over a possibly semi-transparent background.
 #define BLEND_COMPOSITE(d1, d2, d3, da, s1, s2, s3, a) \
 { \
 	if ((da) == 255) { \
@@ -57,8 +74,8 @@ class PatternHandler;
 
 // BLEND_COMPOSITE16
 //
-// this macro assumes source alpha in range 0..65025 and
+// This macro assumes source alpha in range 0..65025 and
-// composes the source color over a possibly semi-transparent background
+// composes the source color over a possibly semi-transparent background.
 // TODO: implement a faster version
 #define BLEND_COMPOSITE16(d1, d2, d3, da, s1, s2, s3, a) \
 { \

src/servers/app/drawing/Painter/drawing_modes/DrawingModeCopy.h

@@ -6,9 +6,9 @@
 #include "DrawingMode.h"
 
 // BLEND_COPY
-#define BLEND_COPY(d1, d2, d3, da, s1, s2, s3, a) \
+#define BLEND_COPY(d1, d2, d3, da, s1, s2, s3, a, l1, l2, l3) \
 { \
-	BLEND(d1, d2, d3, da, s1, s2, s3, a); \
+	BLEND_FROM(d1, d2, d3, da, l1, l2, l3, s1, s2, s3, a); \
 }
 
 // ASSIGN_COPY
@@ -41,8 +41,10 @@ class DrawingModeCopy : public DrawingMode {
 			ASSIGN_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
 						color.red, color.green, color.blue);
 		} else {
+			rgb_color l = fPatternHandler->LowColor().GetColor32();
 			BLEND_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
-					   color.red, color.green, color.blue, cover);
+					   color.red, color.green, color.blue, cover,
+					   l.red, l.green, l.blue);
 		}
 	}
 
@@ -50,7 +52,7 @@ class DrawingModeCopy : public DrawingMode {
 	virtual	void blend_hline(int x, int y, unsigned len, 
 							 const color_type& c, uint8 cover)
 	{
-		if(cover == 255) {
+		if (cover == 255) {
 			// cache the low and high color as 32bit values
 			// high color
 			rgb_color color = fPatternHandler->HighColor().GetColor32();
@@ -80,10 +82,12 @@ class DrawingModeCopy : public DrawingMode {
 			} while(--len);
 		} else {
 			uint8* p = fBuffer->row(y) + (x << 2);
+			rgb_color l = fPatternHandler->LowColor().GetColor32();
 			do {
 				rgb_color color = fPatternHandler->R5ColorAt(x, y);
 				BLEND_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
-						   color.red, color.green, color.blue, cover);
+						   color.red, color.green, color.blue, cover,
+						   l.red, l.green, l.blue);
 				x++;
 				p += 4;
 			} while(--len);
@@ -102,6 +106,7 @@ printf("DrawingModeCopy::blend_vline()\n");
 								   const color_type& c, const uint8* covers)
 	{
 		uint8* p = fBuffer->row(y) + (x << 2);
+		rgb_color l = fPatternHandler->LowColor().GetColor32();
 		do {
 			rgb_color color = fPatternHandler->R5ColorAt(x, y);
 			if (*covers) {
@@ -110,7 +115,8 @@ printf("DrawingModeCopy::blend_vline()\n");
 								color.red, color.green, color.blue);
 				} else {
 					BLEND_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
-							   color.red, color.green, color.blue, *covers);
+							   color.red, color.green, color.blue, *covers,
+							   l.red, l.green, l.blue);
 				}
 			}
 			covers++;
@@ -126,6 +132,7 @@ printf("DrawingModeCopy::blend_vline()\n");
 								   const color_type& c, const uint8* covers)
 	{
 		uint8* p = fBuffer->row(y) + (x << 2);
+		rgb_color l = fPatternHandler->LowColor().GetColor32();
 		do {
 			rgb_color color = fPatternHandler->R5ColorAt(x, y);
 			if (*covers) {
@@ -134,7 +141,8 @@ printf("DrawingModeCopy::blend_vline()\n");
 								color.red, color.green, color.blue);
 				} else {
 					BLEND_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
-							   color.red, color.green, color.blue, *covers);
+							   color.red, color.green, color.blue, *covers,
+							   l.red, l.green, l.blue);
 				}
 			}
 			covers++;
@@ -151,6 +159,7 @@ printf("DrawingModeCopy::blend_vline()\n");
 								   uint8 cover)
 	{
 		uint8* p = fBuffer->row(y) + (x << 2);
+		rgb_color l = fPatternHandler->LowColor().GetColor32();
 		if (covers) {
 			// non-solid opacity
 			do {
@@ -160,7 +169,8 @@ printf("DrawingModeCopy::blend_vline()\n");
 									colors->r, colors->g, colors->b);
 					} else {
 						BLEND_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
-								   colors->r, colors->g, colors->b, *covers);
+								   colors->r, colors->g, colors->b, *covers,
+								   l.red, l.green, l.blue);
 					}
 				}
 				covers++;
@@ -180,7 +190,8 @@ printf("DrawingModeCopy::blend_vline()\n");
 			} else if (cover) {
 				do {
 					BLEND_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
-							   colors->r, colors->g, colors->b, cover);
+							   colors->r, colors->g, colors->b, cover,
+							   l.red, l.green, l.blue);
 					p += 4;
 					++colors;
 				} while(--len);

src/servers/app/drawing/Painter/drawing_modes/DrawingModeCopySolid.h

@@ -22,8 +22,10 @@ class DrawingModeCopySolid : public DrawingMode {
 			ASSIGN_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
 						c.r, c.g, c.b);
 		} else {
+			rgb_color l = fPatternHandler->LowColor().GetColor32();
 			BLEND_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
-					   c.r, c.g, c.b, cover);
+					   c.r, c.g, c.b, cover,
+					   l.red, l.green, l.blue);
 		}
 	}
 
@@ -47,9 +49,11 @@ class DrawingModeCopySolid : public DrawingMode {
 			} while(--len);
 		} else {
 			uint8* p = fBuffer->row(y) + (x << 2);
+			rgb_color l = fPatternHandler->LowColor().GetColor32();
 			do {
 				BLEND_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
-						   c.r, c.g, c.b, cover);
+						   c.r, c.g, c.b, cover,
+						   l.red, l.green, l.blue);
 				p += 4;
 			} while(--len);
 		}
@@ -67,6 +71,7 @@ printf("DrawingModeCopySolid::blend_vline()\n");
 								   const color_type& c, const uint8* covers)
 	{
 		uint8* p = fBuffer->row(y) + (x << 2);
+		rgb_color l = fPatternHandler->LowColor().GetColor32();
 		do {
 			if (*covers) {
 				if(*covers == 255) {
@@ -74,7 +79,8 @@ printf("DrawingModeCopySolid::blend_vline()\n");
 								c.r, c.g, c.b);
 				} else {
 					BLEND_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
-							   c.r, c.g, c.b, *covers);
+							   c.r, c.g, c.b, *covers,
+							   l.red, l.green, l.blue);
 				}
 			}
 			covers++;
@@ -89,6 +95,7 @@ printf("DrawingModeCopySolid::blend_vline()\n");
 								   const color_type& c, const uint8* covers)
 	{
 		uint8* p = fBuffer->row(y) + (x << 2);
+		rgb_color l = fPatternHandler->LowColor().GetColor32();
 		do {
 			if (*covers) {
 				if (*covers == 255) {
@@ -96,7 +103,8 @@ printf("DrawingModeCopySolid::blend_vline()\n");
 								c.r, c.g, c.b);
 				} else {
 					BLEND_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
-							   c.r, c.g, c.b, *covers);
+							   c.r, c.g, c.b, *covers,
+							   l.red, l.green, l.blue);
 				}
 			}
 			covers++;
@@ -112,6 +120,7 @@ printf("DrawingModeCopySolid::blend_vline()\n");
 								   uint8 cover)
 	{
 		uint8* p = fBuffer->row(y) + (x << 2);
+		rgb_color l = fPatternHandler->LowColor().GetColor32();
 		if (covers) {
 			// non-solid opacity
 			do {
@@ -121,7 +130,8 @@ printf("DrawingModeCopySolid::blend_vline()\n");
 									colors->r, colors->g, colors->b);
 					} else {
 						BLEND_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
-								   colors->r, colors->g, colors->b, *covers);
+								   colors->r, colors->g, colors->b, *covers,
+								   l.red, l.green, l.blue);
 					}
 				}
 				covers++;
@@ -141,7 +151,8 @@ printf("DrawingModeCopySolid::blend_vline()\n");
 			} else if (cover) {
 				do {
 					BLEND_COPY(p[Order::R], p[Order::G], p[Order::B], p[Order::A],
-							   colors->r, colors->g, colors->b, cover);
+							   colors->r, colors->g, colors->b, cover,
+							   l.red, l.green, l.blue);
 					p += 4;
 					++colors;
 				} while(--len);

src/servers/app/drawing/Painter/drawing_modes/DrawingModeFactory.cpp

@@ -86,9 +86,9 @@ DrawingModeFactory::DrawingModeFor(drawing_mode mode,
 		// in these drawing modes, the current high
 		// and low color are treated equally
 		case B_OP_COPY:
-			if (solid) {
+			if (solid)
 				return fDrawingModeBGRA32CopySolid;
-			} else
+			else
 				return fDrawingModeBGRA32Copy;
 			break;
 		case B_OP_ADD: