update save/restore comments to mention that the drawFilter is also saved

add wrapper for harfbuzz font/fontclass



git-svn-id: http://skia.googlecode.com/svn/trunk@500 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 195 insertions, 0 deletions

diff --git a/src/ports/SkHarfBuzzFont.cpp b/src/ports/SkHarfBuzzFont.cpp
new file mode 100644
index 0000000000..bb229a1ad6
--- /dev/null
+++ b/src/ports/SkHarfBuzzFont.cpp
@@ -0,0 +1,195 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "SkHarfBuzzFont.h"
+#include "SkFontHost.h"
+#include "SkPaint.h"
+#include "SkPath.h"
+
+// HB_Fixed is a 26.6 fixed point format.
+static inline HB_Fixed SkScalarToHarfbuzzFixed(SkScalar value) {
+#ifdef SK_SCALAR_IS_FLOAT
+    return static_cast<HB_Fixed>(value * 64);
+#else
+    // convert .16 to .6
+    return value >> (16 - 6);
+#endif
+}
+
+static HB_Bool stringToGlyphs(HB_Font hbFont, const HB_UChar16* characters,
+                              hb_uint32 length, HB_Glyph* glyphs,
+                              hb_uint32* glyphsSize, HB_Bool isRTL) {
+    SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData);
+    SkPaint paint;
+
+    paint.setTypeface(font->getTypeface());
+    paint.setTextEncoding(SkPaint::kUTF16_TextEncoding);
+    int numGlyphs = paint.textToGlyphs(characters, length * sizeof(uint16_t),
+                                       reinterpret_cast<uint16_t*>(glyphs));
+
+    // HB_Glyph is 32-bit, but Skia outputs only 16-bit numbers. So our
+    // |glyphs| array needs to be converted.
+    for (int i = numGlyphs - 1; i >= 0; --i) {
+        uint16_t value;
+        // We use a memcpy to avoid breaking strict aliasing rules.
+        memcpy(&value, reinterpret_cast<char*>(glyphs) + sizeof(uint16_t) * i, sizeof(uint16_t));
+        glyphs[i] = value;
+    }
+
+    *glyphsSize = numGlyphs;
+    return 1;
+}
+
+static void glyphsToAdvances(HB_Font hbFont, const HB_Glyph* glyphs,
+                         hb_uint32 numGlyphs, HB_Fixed* advances, int flags) {
+    SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData);
+    SkPaint paint;
+
+    font->setupPaint(&paint);
+    paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
+
+    SkAutoMalloc storage(numGlyphs * (sizeof(SkScalar) + sizeof(uint16_t)));
+    SkScalar* scalarWidths = reinterpret_cast<SkScalar*>(storage.get());
+    uint16_t* glyphs16 = reinterpret_cast<uint16_t*>(scalarWidths + numGlyphs);
+
+    // convert HB 32bit glyphs to skia's 16bit
+    for (hb_uint32 i = 0; i < numGlyphs; ++i) {
+        glyphs16[i] = SkToU16(glyphs[i]);
+    }
+    paint.getTextWidths(glyphs16, numGlyphs * sizeof(uint16_t), scalarWidths);
+
+    for (hb_uint32 i = 0; i < numGlyphs; ++i) {
+        advances[i] = SkScalarToHarfbuzzFixed(scalarWidths[i]);
+    }
+}
+
+static HB_Bool canRender(HB_Font hbFont, const HB_UChar16* characters,
+                         hb_uint32 length) {
+    SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData);
+    SkPaint paint;
+
+    paint.setTypeface(font->getTypeface());
+    paint.setTextEncoding(SkPaint::kUTF16_TextEncoding);
+    return paint.containsText(characters, length * sizeof(uint16_t));
+}
+
+static HB_Error getOutlinePoint(HB_Font hbFont, HB_Glyph glyph, int flags,
+                                hb_uint32 index, HB_Fixed* xPos, HB_Fixed* yPos,
+                                hb_uint32* resultingNumPoints) {
+    SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData);
+    SkPaint paint;
+
+    font->setupPaint(&paint);
+    paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
+    if (flags & HB_ShaperFlag_UseDesignMetrics) {
+        paint.setHinting(SkPaint::kNo_Hinting);
+    }
+
+    SkPath path;
+    uint16_t glyph16 = SkToU16(glyph);
+    paint.getTextPath(&glyph16, sizeof(glyph16), 0, 0, &path);
+    int numPoints = path.countPoints();
+    if (index >= numPoints) {
+        return HB_Err_Invalid_SubTable;
+    }
+
+    SkPoint pt = path.getPoint(index);
+    *xPos = SkScalarToHarfbuzzFixed(pt.fX);
+    *yPos = SkScalarToHarfbuzzFixed(pt.fY);
+    *resultingNumPoints = numPoints;
+
+    return HB_Err_Ok;
+}
+
+static void getGlyphMetrics(HB_Font hbFont, HB_Glyph glyph,
+                            HB_GlyphMetrics* metrics) {
+    SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData);
+    SkPaint paint;
+
+    font->setupPaint(&paint);
+    paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
+
+    SkScalar width;
+    SkRect bounds;
+    uint16_t glyph16 = SkToU16(glyph);
+    paint.getTextWidths(&glyph16, sizeof(glyph16), &width, &bounds);
+
+    metrics->x = SkScalarToHarfbuzzFixed(bounds.fLeft);
+    metrics->y = SkScalarToHarfbuzzFixed(bounds.fTop);
+    metrics->width = SkScalarToHarfbuzzFixed(bounds.width());
+    metrics->height = SkScalarToHarfbuzzFixed(bounds.height());
+
+    metrics->xOffset = SkScalarToHarfbuzzFixed(width);
+    // We can't actually get the |y| correct because Skia doesn't export
+    // the vertical advance. However, nor we do ever render vertical text at
+    // the moment so it's unimportant.
+    metrics->yOffset = 0;
+}
+
+static HB_Fixed getFontMetric(HB_Font hbFont, HB_FontMetric metric)
+{
+    SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData);
+    SkPaint paint;
+    SkPaint::FontMetrics skiaMetrics;
+
+    font->setupPaint(&paint);
+    paint.getFontMetrics(&skiaMetrics);
+
+    switch (metric) {
+    case HB_FontAscent:
+        return SkScalarToHarfbuzzFixed(-skiaMetrics.fAscent);
+    default:
+        SkDebugf("--- unknown harfbuzz metric enum %d\n", metric);
+        return 0;
+    }
+}
+
+static HB_FontClass gSkHarfBuzzFontClass = {
+    stringToGlyphs,
+    glyphsToAdvances,
+    canRender,
+    getOutlinePoint,
+    getGlyphMetrics,
+    getFontMetric,
+};
+
+const HB_FontClass& SkHarfBuzzFont::GetFontClass() {
+    return gSkHarfBuzzFontClass;
+}
+
+HB_Error SkHarfBuzzFont::GetFontTableFunc(void* voidface, const HB_Tag tag,
+                                          HB_Byte* buffer, HB_UInt* len) {
+    SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(voidface);
+    uint32_t uniqueID = SkTypeface::UniqueID(font->getTypeface());
+
+    const size_t tableSize = SkFontHost::GetTableSize(uniqueID, tag);
+    if (!tableSize) {
+        return HB_Err_Invalid_Argument;
+    }
+    // If Harfbuzz specified a NULL buffer then it's asking for the size.
+    if (!buffer) {
+        *len = tableSize;
+        return HB_Err_Ok;
+    }
+
+    if (*len < tableSize) {
+        // is this right, or should we just copy less than the full table?
+        return HB_Err_Invalid_Argument;
+    }
+    SkFontHost::GetTableData(uniqueID, tag, 0, tableSize, buffer);
+    return HB_Err_Ok;
+}
+