Fixed rounding problem in subpixel rendering

git-svn-id: svn://ultimatepp.org/upp/trunk@899 f0d560ea-af0d-0410-9eb7-867de7ffcac7

uppsrc/Painter/Fillers.cpp

@@ -128,10 +128,9 @@ void SubpixelFiller::Render(int val)
 	v++;
 }
 
-void SubpixelFiller::RenderN(int val, int n)
+void SubpixelFiller::RenderN(int val, int h, int n)
 {
 	int16 *w = v;
-	int h = val / 9;
 	int h2 = h + h;
 	int hv2 = val - h2 - h2;
 	int h3 = h2 + h;
@@ -214,11 +213,12 @@ void SubpixelFiller::RenderN(int val, int n)
 
 void SubpixelFiller::Render(int val, int len)
 {
+	int h = val / 9;
 	if(len > 6) {
 		int q = (3333333 - (v + 2 - begin)) % 3;
 		len -= q + 2;
 		int l = v + 2 + q - begin;
-		RenderN(val, q + 4);
+		RenderN(val, h, q + 4);
 		Write(l / 3);
 		l = len / 3;
 		len -= 3 * l;
@@ -235,12 +235,11 @@ void SubpixelFiller::Render(int val, int len)
 			while(t < e)
 				AlphaBlendCover8(*t++, ss ? Mul8(*s++, alpha) : color, val);
 		v = begin = sbuffer + 3;
-		int h = val / 9;
 		v[0] = h + h + h;
 		v[1] = h;
 		v[2] = 0;
 	}
-	RenderN(val, len);
+	RenderN(val, h, len);
 }
 
 void SubpixelFiller::Write(int len)
@@ -249,30 +248,23 @@ void SubpixelFiller::Write(int len)
 	int16 *q = begin;
 	while(t < e) {
 		RGBA c = ss ? Mul8(*s++, alpha) : color;
-		int a, alpha;
+		int a;
 		if(t->a != 255)
 			AlphaBlendCover8(*t, c, (q[0] + q[1] + q[2]) / 3);
-		else {
+		else
 			if(c.a == 255) {
-				alpha = 256 - q[0];
-				t->r = (c.r * q[0] >> 8) + (alpha * t->r >> 8);
-				alpha = 256 - q[1];
-				t->g = (c.g * q[1] >> 8) + (alpha * t->g >> 8);
-				alpha = 256 - q[2];
-				t->b = (c.b * q[2] >> 8) + (alpha * t->b >> 8);
+				t->r = (c.r * q[0] >> 8) + ((257 - q[0]) * t->r >> 8);
+				t->g = (c.g * q[1] >> 8) + ((257 - q[1]) * t->g >> 8);
+				t->b = (c.b * q[2] >> 8) + ((257 - q[2]) * t->b >> 8);
 			}
 			else {
 				a = c.a * q[0] >> 8;
-				alpha = 256 - a - (a >> 7);
-				t->r = (c.r * q[0] >> 8) + (alpha * t->r >> 8);
+				t->r = (c.r * q[0] >> 8) + ((256 - a - (a >> 7)) * t->r >> 8);
 				a = c.a * q[1] >> 8;
-				alpha = 256 - a - (a >> 7);
-				t->g = (c.g * q[1] >> 8) + (alpha * t->g >> 8);
+				t->g = (c.g * q[1] >> 8) + ((256 - a - (a >> 7)) * t->g >> 8);
 				a = c.a * q[2] >> 8;
-				alpha = 256 - a - (a >> 7);
-				t->b = (c.b * q[2] >> 8) + (alpha * t->b >> 8);
+				t->b = (c.b * q[2] >> 8) + ((256 - a - (a >> 7)) * t->b >> 8);
 			}
-		}
 		t++;
 		q += 3;
 	}

uppsrc/Painter/Fillers.h

@@ -35,7 +35,7 @@ struct SubpixelFiller : Rasterizer::Filler {
 	int           y;
 
 	void Write(int len);
-	void RenderN(int val, int n);
+	void RenderN(int val, int h, int n);
 	void Render2(int val);
 	void Render1(int val);
 

uppsrc/Painter/FontWin32.cpp

@@ -21,39 +21,38 @@ NAMESPACE_UPP
 
 #ifdef PLATFORM_WIN32
 
-inline double fx_to_dbl(const FIXED& p) {
+double fx_to_dbl(const FIXED& p) {
 	return double(p.value) + double(p.fract) * (1.0 / 65536.0);
 }
 
+Pointf fx_to_dbl(const Pointf& pp, const POINTFX& p) {
+	return Pointf(pp.x + fx_to_dbl(p.x), pp.y - fx_to_dbl(p.y));
+}
+
 void RenderCharPath(const char* gbuf, unsigned total_size, Painter& sw, double xx, double yy)
 {
 	PAINTER_TIMING("RenderCharPath");
 	const char* cur_glyph = gbuf;
 	const char* end_glyph = gbuf + total_size;
-	
+	Pointf pp(xx, yy);
 	while(cur_glyph < end_glyph) {
 		const TTPOLYGONHEADER* th = (TTPOLYGONHEADER*)cur_glyph;
 		const char* end_poly = cur_glyph + th->cb;
 		const char* cur_poly = cur_glyph + sizeof(TTPOLYGONHEADER);
-		sw.Move(xx + fx_to_dbl(th->pfxStart.x), yy - fx_to_dbl(th->pfxStart.y));
+		sw.Move(fx_to_dbl(pp, th->pfxStart));
 		while(cur_poly < end_poly) {
 			const TTPOLYCURVE* pc = (const TTPOLYCURVE*)cur_poly;
 			if (pc->wType == TT_PRIM_LINE)
 				for(int i = 0; i < pc->cpfx; i++)
-					sw.Line(xx + fx_to_dbl(pc->apfx[i].x), yy - fx_to_dbl(pc->apfx[i].y));
-			if (pc->wType == TT_PRIM_QSPLINE) {
-				int u;
-				for (u = 0; u < pc->cpfx - 1; u++) { // Walk through points in spline
-					POINTFX pnt_b = pc->apfx[u];     // B is always the current point
-					POINTFX pnt_c = pc->apfx[u+1];
-					if (u < pc->cpfx - 2) {          // If not on last spline, compute C
-						*(int*)&pnt_c.x = (*(int*)&pnt_b.x + *(int*)&pnt_c.x) / 2;
-						*(int*)&pnt_c.y = (*(int*)&pnt_b.y + *(int*)&pnt_c.y) / 2;
-					}
-					sw.Quadratic(xx + fx_to_dbl(pnt_b.x), yy - fx_to_dbl(pnt_b.y),
-					             xx + fx_to_dbl(pnt_c.x), yy - fx_to_dbl(pnt_c.y));
+					sw.Line(fx_to_dbl(pp, pc->apfx[i]));
+			if (pc->wType == TT_PRIM_QSPLINE)
+				for(int u = 0; u < pc->cpfx - 1; u++) {
+					Pointf b = fx_to_dbl(pp, pc->apfx[u]);
+					Pointf c = fx_to_dbl(pp, pc->apfx[u + 1]);
+					if (u < pc->cpfx - 2)
+						c = Mid(b, c);
+					sw.Quadratic(b, c);
 				}
-			}
 			cur_poly += sizeof(WORD) * 2 + sizeof(POINTFX) * pc->cpfx;
 		}
 		sw.Close();

uppsrc/Painter/Painter.upp

@@ -34,7 +34,8 @@ file
 	Image.cpp optimize_speed,
 	Mask.cpp optimize_speed,
 	Gradient.cpp optimize_speed,
-	RadialGradient.cpp optimize_speed;
+	RadialGradient.cpp optimize_speed,
+	srcimp.tpp;
 
 mainconfig
 	"" = "GUI";

uppsrc/Painter/init

@@ -2,7 +2,7 @@
 #define _Painter_icpp_init_stub
 #include "Core/init"
 #include "CtrlLib/init"
-#define BLITZ_INDEX__ F135B9991BD270784ACE22BD4FFB4267E
+#define BLITZ_INDEX__ F1F279540D3FE6AF9024371A0E93C1FBB
 #include "PaintPainting.icpp"
 #undef BLITZ_INDEX__
 #endif

uppsrc/Painter/srcimp.tpp/SubpixelFiller$en-us.tpp

@@ -0,0 +1,17 @@
+topic "";
+[ $$0,0#00000000000000000000000000000000:Default]
+[H6;0 $$1,0#05600065144404261032431302351956:begin]
+[i448;a25;kKO9;2 $$2,0#37138531426314131252341829483370:codeitem]
+[l288;2 $$3,0#27521748481378242620020725143825:desc]
+[0 $$4,0#96390100711032703541132217272105:end]
+[{_}%EN-US 
+[s1;%- &]
+[s2;:SubpixelFiller`:`:Write`(int`):%- [@(0.0.255) void]_[* Write]([@(0.0.255) int]_[*@3 len])
+&]
+[s3; This function flushes the content of filtered subpixel buffer.&]
+[s0; Important note: due to rounding errors during filtering, sometimes 
+the subpixel value can be 257. This is remedied by using 257 
+instead of 256 in the pixel blending command.&]
+[s0; &]
+[s4; &]
+[s0; ]