Split out SkFontHost_FreeType into common files
Review URL: https://codereview.appspot.com/6442092
git-svn-id: http://skia.googlecode.com/svn/trunk@5246 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/ports/SkFontHost_FreeType_common.cpp b/src/ports/SkFontHost_FreeType_common.cpp
new file mode 100644
index 0000000..91f172b
--- /dev/null
+++ b/src/ports/SkFontHost_FreeType_common.cpp
@@ -0,0 +1,349 @@
+/*
+ * Copyright 2006-2012 The Android Open Source Project
+ * Copyright 2012 Mozilla Foundation
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkColorPriv.h"
+#include "SkFDot6.h"
+#include "SkFontHost_FreeType_common.h"
+#include "SkPath.h"
+
+#include <ft2build.h>
+#include FT_OUTLINE_H
+#include FT_BITMAP_H
+// In the past, FT_GlyphSlot_Own_Bitmap was defined in this header file.
+#include FT_SYNTHESIS_H
+
+static FT_Pixel_Mode compute_pixel_mode(SkMask::Format format) {
+ switch (format) {
+ case SkMask::kBW_Format:
+ return FT_PIXEL_MODE_MONO;
+ case SkMask::kA8_Format:
+ default:
+ return FT_PIXEL_MODE_GRAY;
+ }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+static uint16_t packTriple(unsigned r, unsigned g, unsigned b) {
+ return SkPackRGB16(r >> 3, g >> 2, b >> 3);
+}
+
+static uint16_t grayToRGB16(U8CPU gray) {
+ SkASSERT(gray <= 255);
+ return SkPackRGB16(gray >> 3, gray >> 2, gray >> 3);
+}
+
+static int bittst(const uint8_t data[], int bitOffset) {
+ SkASSERT(bitOffset >= 0);
+ int lowBit = data[bitOffset >> 3] >> (~bitOffset & 7);
+ return lowBit & 1;
+}
+
+template<bool APPLY_PREBLEND>
+static void copyFT2LCD16(const SkGlyph& glyph, const FT_Bitmap& bitmap,
+ int lcdIsBGR, bool lcdIsVert, const uint8_t* tableR,
+ const uint8_t* tableG, const uint8_t* tableB) {
+ if (lcdIsVert) {
+ SkASSERT(3 * glyph.fHeight == bitmap.rows);
+ } else {
+ SkASSERT(glyph.fHeight == bitmap.rows);
+ }
+
+ uint16_t* dst = reinterpret_cast<uint16_t*>(glyph.fImage);
+ const size_t dstRB = glyph.rowBytes();
+ const int width = glyph.fWidth;
+ const uint8_t* src = bitmap.buffer;
+
+ switch (bitmap.pixel_mode) {
+ case FT_PIXEL_MODE_MONO: {
+ for (int y = 0; y < glyph.fHeight; ++y) {
+ for (int x = 0; x < width; ++x) {
+ dst[x] = -bittst(src, x);
+ }
+ dst = (uint16_t*)((char*)dst + dstRB);
+ src += bitmap.pitch;
+ }
+ } break;
+ case FT_PIXEL_MODE_GRAY: {
+ for (int y = 0; y < glyph.fHeight; ++y) {
+ for (int x = 0; x < width; ++x) {
+ dst[x] = grayToRGB16(src[x]);
+ }
+ dst = (uint16_t*)((char*)dst + dstRB);
+ src += bitmap.pitch;
+ }
+ } break;
+ default: {
+ SkASSERT(lcdIsVert || (glyph.fWidth * 3 == bitmap.width));
+ for (int y = 0; y < glyph.fHeight; y++) {
+ if (lcdIsVert) { // vertical stripes
+ const uint8_t* srcR = src;
+ const uint8_t* srcG = srcR + bitmap.pitch;
+ const uint8_t* srcB = srcG + bitmap.pitch;
+ if (lcdIsBGR) {
+ SkTSwap(srcR, srcB);
+ }
+ for (int x = 0; x < width; x++) {
+ dst[x] = packTriple(sk_apply_lut_if<APPLY_PREBLEND>(*srcR++, tableR),
+ sk_apply_lut_if<APPLY_PREBLEND>(*srcG++, tableG),
+ sk_apply_lut_if<APPLY_PREBLEND>(*srcB++, tableB));
+ }
+ src += 3 * bitmap.pitch;
+ } else { // horizontal stripes
+ const uint8_t* triple = src;
+ if (lcdIsBGR) {
+ for (int x = 0; x < width; x++) {
+ dst[x] = packTriple(sk_apply_lut_if<APPLY_PREBLEND>(triple[2], tableR),
+ sk_apply_lut_if<APPLY_PREBLEND>(triple[1], tableG),
+ sk_apply_lut_if<APPLY_PREBLEND>(triple[0], tableB));
+ triple += 3;
+ }
+ } else {
+ for (int x = 0; x < width; x++) {
+ dst[x] = packTriple(sk_apply_lut_if<APPLY_PREBLEND>(triple[0], tableR),
+ sk_apply_lut_if<APPLY_PREBLEND>(triple[1], tableG),
+ sk_apply_lut_if<APPLY_PREBLEND>(triple[2], tableB));
+ triple += 3;
+ }
+ }
+ src += bitmap.pitch;
+ }
+ dst = (uint16_t*)((char*)dst + dstRB);
+ }
+ } break;
+ }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+#define ft2sk(x) SkFixedToScalar(SkFDot6ToFixed(x))
+
+#if FREETYPE_MAJOR >= 2 && FREETYPE_MINOR >= 2
+ #define CONST_PARAM const
+#else // older freetype doesn't use const here
+ #define CONST_PARAM
+#endif
+
+static int move_proc(CONST_PARAM FT_Vector* pt, void* ctx) {
+ SkPath* path = (SkPath*)ctx;
+ path->close(); // to close the previous contour (if any)
+ path->moveTo(ft2sk(pt->x), -ft2sk(pt->y));
+ return 0;
+}
+
+static int line_proc(CONST_PARAM FT_Vector* pt, void* ctx) {
+ SkPath* path = (SkPath*)ctx;
+ path->lineTo(ft2sk(pt->x), -ft2sk(pt->y));
+ return 0;
+}
+
+static int quad_proc(CONST_PARAM FT_Vector* pt0, CONST_PARAM FT_Vector* pt1,
+ void* ctx) {
+ SkPath* path = (SkPath*)ctx;
+ path->quadTo(ft2sk(pt0->x), -ft2sk(pt0->y), ft2sk(pt1->x), -ft2sk(pt1->y));
+ return 0;
+}
+
+static int cubic_proc(CONST_PARAM FT_Vector* pt0, CONST_PARAM FT_Vector* pt1,
+ CONST_PARAM FT_Vector* pt2, void* ctx) {
+ SkPath* path = (SkPath*)ctx;
+ path->cubicTo(ft2sk(pt0->x), -ft2sk(pt0->y), ft2sk(pt1->x),
+ -ft2sk(pt1->y), ft2sk(pt2->x), -ft2sk(pt2->y));
+ return 0;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+void SkScalerContext_FreeType_Base::generateGlyphImage(FT_Face face,
+ const SkGlyph& glyph,
+ SkMaskGamma::PreBlend* maskPreBlend)
+{
+ //Must be careful not to use these if maskPreBlend == NULL
+ const uint8_t* tableR = NULL;
+ const uint8_t* tableG = NULL;
+ const uint8_t* tableB = NULL;
+ if (maskPreBlend) {
+ tableR = maskPreBlend->fR;
+ tableG = maskPreBlend->fG;
+ tableB = maskPreBlend->fB;
+ }
+
+ const bool doBGR = SkToBool(fRec.fFlags & SkScalerContext::kLCD_BGROrder_Flag);
+ const bool doVert = SkToBool(fRec.fFlags & SkScalerContext::kLCD_Vertical_Flag);
+
+ switch ( face->glyph->format ) {
+ case FT_GLYPH_FORMAT_OUTLINE: {
+ FT_Outline* outline = &face->glyph->outline;
+ FT_BBox bbox;
+ FT_Bitmap target;
+
+ if (fRec.fFlags & SkScalerContext::kEmbolden_Flag) {
+ emboldenOutline(face, outline);
+ }
+
+ int dx = 0, dy = 0;
+ if (fRec.fFlags & SkScalerContext::kSubpixelPositioning_Flag) {
+ dx = SkFixedToFDot6(glyph.getSubXFixed());
+ dy = SkFixedToFDot6(glyph.getSubYFixed());
+ // negate dy since freetype-y-goes-up and skia-y-goes-down
+ dy = -dy;
+ }
+ FT_Outline_Get_CBox(outline, &bbox);
+ /*
+ what we really want to do for subpixel is
+ offset(dx, dy)
+ compute_bounds
+ offset(bbox & !63)
+ but that is two calls to offset, so we do the following, which
+ achieves the same thing with only one offset call.
+ */
+ FT_Outline_Translate(outline, dx - ((bbox.xMin + dx) & ~63),
+ dy - ((bbox.yMin + dy) & ~63));
+
+ if (SkMask::kLCD16_Format == glyph.fMaskFormat) {
+ FT_Render_Glyph(face->glyph, doVert ? FT_RENDER_MODE_LCD_V : FT_RENDER_MODE_LCD);
+ if (maskPreBlend) {
+ copyFT2LCD16<true>(glyph, face->glyph->bitmap, doBGR, doVert,
+ tableR, tableG, tableB);
+ } else {
+ copyFT2LCD16<false>(glyph, face->glyph->bitmap, doBGR, doVert,
+ tableR, tableG, tableB);
+ }
+ } else {
+ target.width = glyph.fWidth;
+ target.rows = glyph.fHeight;
+ target.pitch = glyph.rowBytes();
+ target.buffer = reinterpret_cast<uint8_t*>(glyph.fImage);
+ target.pixel_mode = compute_pixel_mode(
+ (SkMask::Format)fRec.fMaskFormat);
+ target.num_grays = 256;
+
+ memset(glyph.fImage, 0, glyph.rowBytes() * glyph.fHeight);
+ FT_Outline_Get_Bitmap(face->glyph->library, outline, &target);
+ }
+ } break;
+
+ case FT_GLYPH_FORMAT_BITMAP: {
+ if (fRec.fFlags & SkScalerContext::kEmbolden_Flag) {
+ FT_GlyphSlot_Own_Bitmap(face->glyph);
+ FT_Bitmap_Embolden(face->glyph->library, &face->glyph->bitmap, kBitmapEmboldenStrength, 0);
+ }
+ SkASSERT_CONTINUE(glyph.fWidth == face->glyph->bitmap.width);
+ SkASSERT_CONTINUE(glyph.fHeight == face->glyph->bitmap.rows);
+ SkASSERT_CONTINUE(glyph.fTop == -face->glyph->bitmap_top);
+ SkASSERT_CONTINUE(glyph.fLeft == face->glyph->bitmap_left);
+
+ const uint8_t* src = (const uint8_t*)face->glyph->bitmap.buffer;
+ uint8_t* dst = (uint8_t*)glyph.fImage;
+
+ if (face->glyph->bitmap.pixel_mode == FT_PIXEL_MODE_GRAY ||
+ (face->glyph->bitmap.pixel_mode == FT_PIXEL_MODE_MONO &&
+ glyph.fMaskFormat == SkMask::kBW_Format)) {
+ unsigned srcRowBytes = face->glyph->bitmap.pitch;
+ unsigned dstRowBytes = glyph.rowBytes();
+ unsigned minRowBytes = SkMin32(srcRowBytes, dstRowBytes);
+ unsigned extraRowBytes = dstRowBytes - minRowBytes;
+
+ for (int y = face->glyph->bitmap.rows - 1; y >= 0; --y) {
+ memcpy(dst, src, minRowBytes);
+ memset(dst + minRowBytes, 0, extraRowBytes);
+ src += srcRowBytes;
+ dst += dstRowBytes;
+ }
+ } else if (face->glyph->bitmap.pixel_mode == FT_PIXEL_MODE_MONO &&
+ glyph.fMaskFormat == SkMask::kA8_Format) {
+ for (int y = 0; y < face->glyph->bitmap.rows; ++y) {
+ uint8_t byte = 0;
+ int bits = 0;
+ const uint8_t* src_row = src;
+ uint8_t* dst_row = dst;
+
+ for (int x = 0; x < face->glyph->bitmap.width; ++x) {
+ if (!bits) {
+ byte = *src_row++;
+ bits = 8;
+ }
+
+ *dst_row++ = byte & 0x80 ? 0xff : 0;
+ bits--;
+ byte <<= 1;
+ }
+
+ src += face->glyph->bitmap.pitch;
+ dst += glyph.rowBytes();
+ }
+ } else if (SkMask::kLCD16_Format == glyph.fMaskFormat) {
+ if (maskPreBlend) {
+ copyFT2LCD16<true>(glyph, face->glyph->bitmap, doBGR, doVert,
+ tableR, tableG, tableB);
+ } else {
+ copyFT2LCD16<false>(glyph, face->glyph->bitmap, doBGR, doVert,
+ tableR, tableG, tableB);
+ }
+ } else {
+ SkDEBUGFAIL("unknown glyph bitmap transform needed");
+ }
+ } break;
+
+ default:
+ SkDEBUGFAIL("unknown glyph format");
+ memset(glyph.fImage, 0, glyph.rowBytes() * glyph.fHeight);
+ return;
+ }
+
+// We used to always do this pre-USE_COLOR_LUMINANCE, but with colorlum,
+// it is optional
+#if defined(SK_GAMMA_APPLY_TO_A8)
+ if (SkMask::kA8_Format == glyph.fMaskFormat && maskPreBlend) {
+ uint8_t* SK_RESTRICT dst = (uint8_t*)glyph.fImage;
+ unsigned rowBytes = glyph.rowBytes();
+
+ for (int y = glyph.fHeight - 1; y >= 0; --y) {
+ for (int x = glyph.fWidth - 1; x >= 0; --x) {
+ dst[x] = tableG[dst[x]];
+ }
+ dst += rowBytes;
+ }
+ }
+#endif
+}
+
+void SkScalerContext_FreeType_Base::generateGlyphPath(FT_Face face,
+ const SkGlyph& glyph,
+ SkPath* path)
+{
+ if (fRec.fFlags & SkScalerContext::kEmbolden_Flag) {
+ emboldenOutline(face, &face->glyph->outline);
+ }
+
+ FT_Outline_Funcs funcs;
+
+ funcs.move_to = move_proc;
+ funcs.line_to = line_proc;
+ funcs.conic_to = quad_proc;
+ funcs.cubic_to = cubic_proc;
+ funcs.shift = 0;
+ funcs.delta = 0;
+
+ FT_Error err = FT_Outline_Decompose(&face->glyph->outline, &funcs, path);
+
+ if (err != 0) {
+ path->reset();
+ return;
+ }
+
+ path->close();
+}
+
+void SkScalerContext_FreeType_Base::emboldenOutline(FT_Face face, FT_Outline* outline)
+{
+ FT_Pos strength;
+ strength = FT_MulFix(face->units_per_EM, face->size->metrics.y_scale)
+ / 24;
+ FT_Outline_Embolden(outline, strength);
+}