[patch] patch for cairo 1.2.*

0001-freetype-Add-fir-filter-for-subpixel-text-rendering-enabled-by-default.diff (text/plain), 7.28 KB, created by Łukasz Mierzwa on 2006-08-29 03:41:57 UTC

From nobody Mon Sep 17 00:00:00 2001
From: Jinghua Luo <[e-mail]>
Date: Thu Jun 22 20:15:48 2006 +0800
Subject: [PATCH] freetype: Add fir filter for subpixel text rendering(enabled by default).

---

 src/cairo-ft-font.c |  230 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 229 insertions(+), 1 deletions(-)

6b0dcf35096721bd1b6f7068c60fa51f8c39c1d8
diff --git a/src/cairo-ft-font.c b/src/cairo-ft-font.c
index 9db46d2..cd92182 100644
--- a/src/cairo-ft-font.c
+++ b/src/cairo-ft-font.c
@@ -52,6 +52,8 @@ #if HAVE_FT_GLYPHSLOT_EMBOLDEN
 #include FT_SYNTHESIS_H
 #endif
 
+#define FIR_FILTER 1
+
 #define DOUBLE_TO_26_6(d) ((FT_F26Dot6)((d) * 64.0))
 #define DOUBLE_FROM_26_6(t) ((double)(t) / 64.0)
 #define DOUBLE_TO_16_16(d) ((FT_Fixed)((d) * 65536.0))
@@ -490,6 +492,8 @@ _cairo_ft_unscaled_font_destroy (void *a
     }
 }
 
+static const int   fir_filter[5] = { 0x1C, 0x38, 0x55, 0x38, 0x1C };
+
 static cairo_bool_t
 _has_unlocked_face (void *entry)
 {
@@ -776,7 +780,220 @@ #endif
 	    }
 	    format = CAIRO_FORMAT_A8;
 	    break;
-	case CAIRO_ANTIALIAS_SUBPIXEL: {
+	case CAIRO_ANTIALIAS_SUBPIXEL:
+#ifdef FIR_FILTER
+	{
+	    unsigned char*  line;
+	    unsigned char*  bufBitmap;
+	    int		    pitch;
+	    unsigned char   *data_rgba;
+	    unsigned int    width_rgba, stride_rgba;
+	    int		    vmul = 1;
+	    int		    hmul = 1;
+
+	    switch (font_options->subpixel_order) {
+	    case CAIRO_SUBPIXEL_ORDER_DEFAULT:
+	    case CAIRO_SUBPIXEL_ORDER_RGB:
+	    case CAIRO_SUBPIXEL_ORDER_BGR:
+	    default:
+		width /= 3;
+		hmul = 3;
+		break;
+	    case CAIRO_SUBPIXEL_ORDER_VRGB:
+	    case CAIRO_SUBPIXEL_ORDER_VBGR:
+		vmul = 3;
+		height /= 3;
+		break;
+	    }
+	    /*
+	     * Filter the glyph to soften the color fringes
+	     */
+	    width_rgba = width;
+	    stride = bitmap->pitch;
+	    stride_rgba = (width_rgba * 4 + 3) & ~3;
+	    data_rgba = calloc (1, stride_rgba * height);
+
+	    /* perform in-place FIR filtering in either the horizontal or
+	     * vertical direction. We're going to modify the RGB graymap,
+	     * but that's ok, because we either own it, or its part of
+	     * the FreeType glyph slot, which will not be used anymore.
+	     */
+	    pitch  = bitmap->pitch;
+	    line   = (unsigned char*)bitmap->buffer;
+	    if ( pitch < 0 )
+		line -= pitch*(height-1);
+
+	    bufBitmap = line;
+
+	    switch (font_options->subpixel_order) {
+	    case CAIRO_SUBPIXEL_ORDER_DEFAULT:
+	    case CAIRO_SUBPIXEL_ORDER_RGB:
+	    case CAIRO_SUBPIXEL_ORDER_BGR:
+	    {
+		int  h;
+
+		for ( h = height; h > 0; h--, line += pitch ) {
+		    int             pix[6] = { 0, 0, 0, 0, 0, 0 };
+		    unsigned char*  p      = line;
+		    unsigned char*  limit  = line + width*3;
+		    int             nn, val, val2;
+
+		    val = p[0];
+		    for (nn = 0; nn < 3; nn++)
+			pix[2 + nn] += val * fir_filter[nn];
+
+		    val = p[1];
+		    for (nn = 0; nn < 4; nn++)
+			pix[1 + nn] += val * fir_filter[nn];
+
+		    p += 2;
+
+		    for ( ; p  < limit; p++ ) {
+			val = p[0];
+			for (nn = 0; nn < 5; nn++)
+			    pix[nn] += val * fir_filter[nn];
+
+			val2  = pix[0] / 256;
+			val2 |= -(val2 >> 8);
+			p[-2]  = (unsigned char)val2;
+
+			for (nn = 0; nn < 5; nn++)
+			    pix[nn] = pix[nn + 1];
+		    }
+		    for (nn = 0; nn < 2; nn++ ) {
+			val2  = pix[nn] / 256;
+			val2 |= -(val2 >> 8);
+			p[nn - 2] = (unsigned char)val2;
+		    }
+		}
+	    }
+	    break;
+	    case CAIRO_SUBPIXEL_ORDER_VRGB:
+	    case CAIRO_SUBPIXEL_ORDER_VBGR:
+	    {
+		int  w;
+
+		for (w = 0; w < width; w++ ) {
+		    int  pix[6] = { 0, 0, 0, 0, 0, 0 };
+		    unsigned char*  p     = bufBitmap + w;
+		    unsigned char*  limit = bufBitmap + w + height*3*pitch;
+		    int             nn, val, val2;
+
+		    val = p[0];
+		    for (nn = 0; nn < 3; nn++)
+			pix[2 + nn] += val*fir_filter[nn];
+
+		    val = p[pitch];
+		    for (nn = 0; nn < 4; nn++ )
+			pix[1 + nn] += val * fir_filter[nn];
+
+		    p += 2*pitch;
+		    for ( ; p < limit; p += pitch ) {
+			val = p[0];
+			for (nn = 0; nn < 5; nn++ )
+			    pix[nn] += val * fir_filter[nn];
+
+			val2  = pix[0] / 256;
+			val2 |= -(val2 >> 8);
+			p[-2 * pitch] = (unsigned char)val2;
+
+			for (nn = 0; nn < 5; nn++)
+			    pix[nn] = pix[nn+1];
+		    }
+
+		    for (nn = 0; nn < 2; nn++) {
+			val2  = pix[nn] / 256;
+			val2 |= -(val2 >> 8);
+			p[(nn - 2) * pitch] = (unsigned char)val2;
+		    }
+		}
+	    }
+	    break;
+	    default:  /* shouldn't happen */
+		break;
+	    }
+
+	    /* now copy the resulting graymap into an ARGB32 image */
+	    {
+		unsigned char*  in_line  = bufBitmap;
+		unsigned char*  out_line = data_rgba;
+		int             h        = height;
+
+		switch (font_options->subpixel_order) {
+		case CAIRO_SUBPIXEL_ORDER_DEFAULT:
+		case CAIRO_SUBPIXEL_ORDER_RGB:
+		    for ( ; h > 0; h--, in_line += pitch, out_line += stride_rgba) {
+			unsigned char*  in  = in_line;
+			int*            out = (int*)out_line;
+			int             w;
+
+			for (w = width; w > 0; w--, in += 3, out += 1) {
+			    int  r = in[0];
+			    int  g = in[1];
+			    int  b = in[2];
+
+			    out[0] = (g << 24) | (r << 16) | (g << 8) | b;
+			}
+		    }
+		    break;
+		case CAIRO_SUBPIXEL_ORDER_BGR:
+		    for ( ; h > 0; h--, in_line += pitch, out_line += stride_rgba) {
+			unsigned char*  in  = in_line;
+			int*            out = (int*)out_line;
+			int             w;
+
+			for (w = width; w > 0; w--, in += 3, out += 1) {
+			    int  r = in[2];
+			    int  g = in[1];
+			    int  b = in[0];
+
+			    out[0] = (g << 24) | (r << 16) | (g << 8) | b;
+			}
+		    }
+		    break;
+		case CAIRO_SUBPIXEL_ORDER_VRGB:
+		    for ( ; h > 0; h--, in_line += pitch*3, out_line += stride_rgba) {
+			unsigned char*  in  = in_line;
+			int*            out = (int*)out_line;
+			int             w;
+
+			for (w = width; w > 0; w--, in += 1, out += 1) {
+			    int  r = in[0];
+			    int  g = in[pitch];
+			    int  b = in[pitch*2];
+
+			    out[0] = (g << 24) | (r << 16) | (g << 8) | b;
+			}
+		    }
+		    break;
+		case CAIRO_SUBPIXEL_ORDER_VBGR:
+		    for ( ; h > 0; h--, in_line += pitch*3, out_line += stride_rgba) {
+			unsigned char*  in  = in_line;
+			int*            out = (int*)out_line;
+			int             w;
+
+			for (w = width; w > 0; w--, in += 1, out += 1) {
+			    int  r = in[2*pitch];
+			    int  g = in[pitch];
+			    int  b = in[0];
+
+			    out[0] = (g << 24) | (r << 16) | (g << 8) | b;
+			}
+		    }
+		    break;
+		}
+	    }
+
+	    if (own_buffer)
+		free (bitmap->buffer);
+	    data = data_rgba;
+	    stride = stride_rgba;
+	    format = CAIRO_FORMAT_ARGB32;
+	    subpixel = TRUE;
+	    break;
+	}
+#else /* !FIR_FILTER */
+	{
 	    int		    x, y;
 	    unsigned char   *in_line, *out_line, *in;
 	    unsigned int    *out;
@@ -868,6 +1085,7 @@ #endif
 	    subpixel = TRUE;
 	    break;
 	}
+#endif /* !FIR_FILTER */
 	}
 	break;
     case FT_PIXEL_MODE_GRAY2:
@@ -982,12 +1200,22 @@ _render_glyph_outline (FT_Face          
 		matrix.xx *= 3;
 		hmul = 3;
 		subpixel = TRUE;
+#ifdef FIR_FILTER
+		cbox.xMin -= 64;
+		cbox.xMax += 64;
+		width    += 2;
+#endif
 		break;
 	    case CAIRO_SUBPIXEL_ORDER_VRGB:
 	    case CAIRO_SUBPIXEL_ORDER_VBGR:
 		matrix.yy *= 3;
 		vmul = 3;
 		subpixel = TRUE;
+#ifdef FIR_FILTER
+		cbox.yMin -= 64;
+		cbox.yMax += 64;
+		height    += 2;
+#endif
 		break;
 	    }
 	    FT_Outline_Transform (outline, &matrix);
-- 
1.3.1