fz_pixmap revamp: add stride and make alpha optional

fz_pixmaps now have an explicit stride value. By default no change
from before, but code all copes with extra gaps at the end of the
line.

The alpha data in fz_pixmaps is no longer compulsory.

mudraw: use rgb not rgba (ppmraw), cmyk not cmyka (pkmraw).

Update halftone code to not expect alpha plane.

Update PNG writing to cope with alpha less input.

Also hide repeated params within the png output context.

ARM code needs updating.

1 files changed, 108 insertions, 54 deletions

diff --git a/source/fitz/draw-blend.c b/source/fitz/draw-blend.c
index 57aa28b1..31914ae1 100644
--- a/source/fitz/draw-blend.c
+++ b/source/fitz/draw-blend.c
@@ -268,15 +268,14 @@ fz_blend_pixel(unsigned char dp[3], unsigned char bp[3], unsigned char sp[3], in
 
 /* Blending loops */
 
-void
-fz_blend_separable(byte * restrict bp, byte * restrict sp, int n, int w, int blendmode)
+static inline void
+fz_blend_separable(byte * restrict bp, int bal, byte * restrict sp, int sal, int n1, int w, int blendmode)
 {
 	int k;
-	int n1 = n - 1;
 	while (w--)
 	{
-		int sa = sp[n1];
-		int ba = bp[n1];
+		int sa = (sal ? sp[n1] : 255);
+		int ba = (bal ? bp[n1] : 255);
 		int saba = fz_mul255(sa, ba);
 
 		/* ugh, division to get non-premul components */
@@ -309,22 +308,23 @@ fz_blend_separable(byte * restrict bp, byte * restrict sp, int n, int w, int ble
 			bp[k] = fz_mul255(255 - sa, bp[k]) + fz_mul255(255 - ba, sp[k]) + fz_mul255(saba, rc);
 		}
 
-		bp[k] = ba + sa - saba;
+		if (bal)
+			bp[k] = ba + sa - saba;
 
-		sp += n;
-		bp += n;
+		sp += n1 + sal;
+		bp += n1 + bal;
 	}
 }
 
-void
-fz_blend_nonseparable(byte * restrict bp, byte * restrict sp, int w, int blendmode)
+static void
+fz_blend_nonseparable(byte * restrict bp, int bal, byte * restrict sp, int sal, int w, int blendmode)
 {
 	while (w--)
 	{
 		unsigned char rr, rg, rb;
 
-		int sa = sp[3];
-		int ba = bp[3];
+		int sa = (sal ? sp[3] : 255);
+		int ba = (bal ? bp[3] : 255);
 		int saba = fz_mul255(sa, ba);
 
 		/* ugh, division to get non-premul components */
@@ -359,18 +359,18 @@ fz_blend_nonseparable(byte * restrict bp, byte * restrict sp, int w, int blendmo
 		bp[0] = fz_mul255(255 - sa, bp[0]) + fz_mul255(255 - ba, sp[0]) + fz_mul255(saba, rr);
 		bp[1] = fz_mul255(255 - sa, bp[1]) + fz_mul255(255 - ba, sp[1]) + fz_mul255(saba, rg);
 		bp[2] = fz_mul255(255 - sa, bp[2]) + fz_mul255(255 - ba, sp[2]) + fz_mul255(saba, rb);
-		bp[3] = ba + sa - saba;
+		if (bal)
+			bp[3] = ba + sa - saba;
 
-		sp += 4;
-		bp += 4;
+		sp += 3 + sal;
+		bp += 3 + bal;
 	}
 }
 
-static void
-fz_blend_separable_nonisolated(byte * restrict bp, byte * restrict sp, int n, int w, int blendmode, byte * restrict hp, int alpha)
+static inline void
+fz_blend_separable_nonisolated(byte * restrict bp, int bal, byte * restrict sp, int sal, int n1, int w, int blendmode, byte * restrict hp, int alpha)
 {
 	int k;
-	int n1 = n - 1;
 
 	if (alpha == 255 && blendmode == 0)
 	{
@@ -384,14 +384,16 @@ fz_blend_separable_nonisolated(byte * restrict bp, byte * restrict sp, int n, in
 			/* If ha == 0 then leave everything unchanged */
 			if (ha != 0)
 			{
-				for (k = 0; k < n; k++)
+				for (k = 0; k < n1; k++)
 				{
 					bp[k] = sp[k];
 				}
+				if (bal)
+					bp[k] = (sal ? sp[k] : 255);
 			}
 
-			sp += n;
-			bp += n;
+			sp += n1 + sal;
+			bp += n1 + bal;
 		}
 		return;
 	}
@@ -403,11 +405,11 @@ fz_blend_separable_nonisolated(byte * restrict bp, byte * restrict sp, int n, in
 		while (haa != 0) /* Use while, so we can break out */
 		{
 			int sa, ba, bahaa, ra, invsa, invba, invha, invra;
-			sa = sp[n1];
+			sa = (sal ? sp[n1] : 255);
 			if (sa == 0)
 				break; /* No change! */
 			invsa = sa ? 255 * 256 / sa : 0;
-			ba = bp[n1];
+			ba = (bal ? bp[n1] : 255);
 			if (ba == 0)
 			{
 				/* Just copy pixels (allowing for change in
@@ -416,7 +418,8 @@ fz_blend_separable_nonisolated(byte * restrict bp, byte * restrict sp, int n, in
 				{
 					bp[k] = fz_mul255((sp[k] * invsa) >> 8, haa);
 				}
-				bp[n1] = haa;
+				if (bal)
+					bp[n1] = haa;
 				break;
 			}
 			bahaa = fz_mul255(ba, haa);
@@ -426,7 +429,9 @@ fz_blend_separable_nonisolated(byte * restrict bp, byte * restrict sp, int n, in
 
 			/* Calculate result_alpha - a combination of the
 			 * background alpha, and 'shape' */
-			ra = bp[n1] = ba - bahaa + haa;
+			ra = ba - bahaa + haa;
+			if (bal)
+				bp[n1] = ra;
 			if (ra == 0)
 				break;
 			/* Because we are a non-isolated group, we need to
@@ -483,18 +488,18 @@ fz_blend_separable_nonisolated(byte * restrict bp, byte * restrict sp, int n, in
 				rc = bc + fz_mul255(sa, fz_mul255(255 - ba, sc) + fz_mul255(ba, rc) - bc);
 				if (rc < 0) rc = 0;
 				if (rc > 255) rc = 255;
-				bp[k] = fz_mul255(rc, ra);
+					bp[k] = fz_mul255(rc, ra);
 			}
 			break;
 		}
 
-		sp += n;
-		bp += n;
+		sp += n1 + sal;
+		bp += n1 + bal;
 	}
 }
 
-static void
-fz_blend_nonseparable_nonisolated(byte * restrict bp, byte * restrict sp, int w, int blendmode, byte * restrict hp, int alpha)
+static inline void
+fz_blend_nonseparable_nonisolated(byte * restrict bp, int bal, byte * restrict sp, int sal, int w, int blendmode, byte * restrict hp, int alpha)
 {
 	while (w--)
 	{
@@ -502,12 +507,14 @@ fz_blend_nonseparable_nonisolated(byte * restrict bp, byte * restrict sp, int w,
 		int haa = fz_mul255(ha, alpha);
 		if (haa != 0)
 		{
-			int sa = sp[3];
-			int ba = bp[3];
+			int sa = (sal ? sp[3] : 255);
+			int ba = (bal ? bp[3] : 255);
 			int baha = fz_mul255(ba, haa);
 
 			/* Calculate result_alpha */
-			int ra = bp[3] = ba - baha + haa;
+			int ra = ba - baha + haa;
+			if (bal)
+				bp[3] = ra;
 			if (ra != 0)
 			{
 				/* Because we are a non-isolated group, we
@@ -566,8 +573,8 @@ fz_blend_nonseparable_nonisolated(byte * restrict bp, byte * restrict sp, int w,
 			}
 		}
 
-		sp += 4;
-		bp += 4;
+		sp += 3 + sal;
+		bp += 3 + bal;
 	}
 }
 
@@ -578,16 +585,24 @@ fz_blend_pixmap(fz_pixmap *dst, fz_pixmap *src, int alpha, int blendmode, int is
 	fz_irect bbox;
 	fz_irect bbox2;
 	int x, y, w, h, n;
+	int da, sa;
 
 	/* TODO: fix this hack! */
 	if (isolated && alpha < 255)
 	{
+		int nn;
+		h = src->h;
 		sp = src->samples;
-		n = src->w * src->h * src->n;
-		while (n--)
+		nn = src->w * src->n;
+		while (h--)
 		{
-			*sp = fz_mul255(*sp, alpha);
-			sp++;
+			n = nn;
+			while (n--)
+			{
+				*sp = fz_mul255(*sp, alpha);
+				sp++;
+			}
+			sp += src->stride - nn;
 		}
 	}
 
@@ -601,36 +616,75 @@ fz_blend_pixmap(fz_pixmap *dst, fz_pixmap *src, int alpha, int blendmode, int is
 	h = bbox.y1 - bbox.y0;
 
 	n = src->n;
-	sp = src->samples + (unsigned int)(((y - src->y) * src->w + (x - src->x)) * n);
-	dp = dst->samples + (unsigned int)(((y - dst->y) * dst->w + (x - dst->x)) * n);
+	sp = src->samples + (unsigned int)((y - src->y) * src->stride + (x - src->x) * src->n);
+	sa = src->alpha;
+	dp = dst->samples + (unsigned int)((y - dst->y) * dst->stride + (x - dst->x) * dst->n);
+	da = dst->alpha;
 
-	assert(src->n == dst->n);
+	n -= sa;
+	assert(n == dst->n - da);
 
 	if (!isolated)
 	{
-		unsigned char *hp = shape->samples + (unsigned int)((y - shape->y) * shape->w + (x - shape->x));
+		unsigned char *hp = shape->samples + (unsigned int)((y - shape->y) * shape->stride + (x - shape->x));
 
 		while (h--)
 		{
-			if (n == 4 && blendmode >= FZ_BLEND_HUE)
-				fz_blend_nonseparable_nonisolated(dp, sp, w, blendmode, hp, alpha);
+			if (n == 3 && blendmode >= FZ_BLEND_HUE)
+				if (da)
+					if (sa)
+						fz_blend_nonseparable_nonisolated(dp, 1, sp, 1, w, blendmode, hp, alpha);
+					else
+						fz_blend_nonseparable_nonisolated(dp, 1, sp, 0, w, blendmode, hp, alpha);
+				else
+					if (sa)
+						fz_blend_nonseparable_nonisolated(dp, 0, sp, 1, w, blendmode, hp, alpha);
+					else
+						fz_blend_nonseparable_nonisolated(dp, 0, sp, 0, w, blendmode, hp, alpha);
 			else
-				fz_blend_separable_nonisolated(dp, sp, n, w, blendmode, hp, alpha);
-			sp += src->w * n;
-			dp += dst->w * n;
-			hp += shape->w;
+				if (da)
+					if (sa)
+						fz_blend_separable_nonisolated(dp, 1, sp, 1, n, w, blendmode, hp, alpha);
+					else
+						fz_blend_separable_nonisolated(dp, 1, sp, 0, n, w, blendmode, hp, alpha);
+				else
+					if (sa)
+						fz_blend_separable_nonisolated(dp, 0, sp, 1, n, w, blendmode, hp, alpha);
+					else
+						fz_blend_separable_nonisolated(dp, 0, sp, 0, n, w, blendmode, hp, alpha);
+			sp += src->stride;
+			dp += dst->stride;
+			hp += shape->stride;
 		}
 	}
 	else
 	{
 		while (h--)
 		{
-			if (n == 4 && blendmode >= FZ_BLEND_HUE)
-				fz_blend_nonseparable(dp, sp, w, blendmode);
+			if (n == 3 && blendmode >= FZ_BLEND_HUE)
+				if (da)
+					if (sa)
+						fz_blend_nonseparable(dp, 1, sp, 1, w, blendmode);
+					else
+						fz_blend_nonseparable(dp, 1, sp, 0, w, blendmode);
+				else
+					if (sa)
+						fz_blend_nonseparable(dp, 0, sp, 1, w, blendmode);
+					else
+						fz_blend_nonseparable(dp, 0, sp, 0, w, blendmode);
 			else
-				fz_blend_separable(dp, sp, n, w, blendmode);
-			sp += src->w * n;
-			dp += dst->w * n;
+				if (da)
+					if (sa)
+						fz_blend_separable(dp, 1, sp, 1, n, w, blendmode);
+					else
+						fz_blend_separable(dp, 1, sp, 0, n, w, blendmode);
+				else
+					if (sa)
+						fz_blend_separable(dp, 0, sp, 1, n, w, blendmode);
+					else
+						fz_blend_separable(dp, 0, sp, 0, n, w, blendmode);
+			sp += src->stride;
+			dp += dst->stride;
 		}
 	}
 }