Support 3D rotations when drawing text
If a perspective transform is set on the Canvas, drawText() should
not attempt to rasterize glyphs in screen space. This change uses
the old behavior instead (i.e. rasterize the glyphs at the native
font size and apply the transform on the resulting mesh.)
This change also adds an optimization: empty glyphs (spaces) do
not generate vertices anymore. This saves a lot of vertices in text
heavy applications such as Gmail.
Change-Id: Ib531384163f5165b5785501612a7b1474f3ff599
diff --git a/libs/hwui/font/Font.cpp b/libs/hwui/font/Font.cpp
index ea9fd03..d48b612 100644
--- a/libs/hwui/font/Font.cpp
+++ b/libs/hwui/font/Font.cpp
@@ -52,6 +52,7 @@
mStyle = paint->getStyle();
mStrokeWidth = paint->getStrokeWidth();
mAntiAliasing = paint->isAntiAlias();
+ mLookupTransform.reset();
mLookupTransform[SkMatrix::kMScaleX] = matrix.data[mat4::kScaleX];
mLookupTransform[SkMatrix::kMScaleY] = matrix.data[mat4::kScaleY];
mLookupTransform[SkMatrix::kMSkewX] = matrix.data[mat4::kSkewX];
@@ -165,7 +166,7 @@
void Font::drawCachedGlyph(CachedGlyphInfo* glyph, int x, int y,
uint8_t* bitmap, uint32_t bitmapW, uint32_t bitmapH, Rect* bounds, const float* pos) {
float nPenX = x + glyph->mBitmapLeft;
- float nPenY = y + (glyph->mBitmapTop + glyph->mBitmapHeight);
+ float nPenY = y + glyph->mBitmapTop + glyph->mBitmapHeight;
float width = (float) glyph->mBitmapWidth;
float height = (float) glyph->mBitmapHeight;
@@ -181,6 +182,38 @@
nPenX, nPenY - height, u1, v1, glyph->mCacheTexture);
}
+void Font::drawCachedGlyphPerspective(CachedGlyphInfo* glyph, int x, int y,
+ uint8_t* bitmap, uint32_t bitmapW, uint32_t bitmapH, Rect* bounds, const float* pos) {
+ SkMatrix i;
+ if (!mDescription.mLookupTransform.invert(&i)) {
+ return;
+ }
+
+ SkPoint p[4];
+ p[0].set(glyph->mBitmapLeft, glyph->mBitmapTop + glyph->mBitmapHeight);
+ p[1].set(glyph->mBitmapLeft + glyph->mBitmapWidth, glyph->mBitmapTop + glyph->mBitmapHeight);
+ p[2].set(glyph->mBitmapLeft + glyph->mBitmapWidth, glyph->mBitmapTop);
+ p[3].set(glyph->mBitmapLeft, glyph->mBitmapTop);
+
+ i.mapPoints(p, 4);
+
+ p[0].offset(x, y);
+ p[1].offset(x, y);
+ p[2].offset(x, y);
+ p[3].offset(x, y);
+
+ float u1 = glyph->mBitmapMinU;
+ float u2 = glyph->mBitmapMaxU;
+ float v1 = glyph->mBitmapMinV;
+ float v2 = glyph->mBitmapMaxV;
+
+ mState->appendRotatedMeshQuad(
+ p[0].fX, p[0].fY, u1, v2,
+ p[1].fX, p[1].fY, u2, v2,
+ p[2].fX, p[2].fY, u2, v1,
+ p[3].fX, p[3].fY, u1, v1, glyph->mCacheTexture);
+}
+
void Font::drawCachedGlyphBitmap(CachedGlyphInfo* glyph, int x, int y,
uint8_t* bitmap, uint32_t bitmapW, uint32_t bitmapH, Rect* bounds, const float* pos) {
int nPenX = x + glyph->mBitmapLeft;
@@ -307,7 +340,7 @@
penX += SkFixedToFloat(AUTO_KERN(prevRsbDelta, cachedGlyph->mLsbDelta));
prevRsbDelta = cachedGlyph->mRsbDelta;
- if (cachedGlyph->mIsValid) {
+ if (cachedGlyph->mIsValid && cachedGlyph->mCacheTexture) {
drawCachedGlyph(cachedGlyph, penX, hOffset, vOffset, measure, &position, &tangent);
}
@@ -328,7 +361,6 @@
}
void Font::precache(SkPaint* paint, const char* text, int numGlyphs) {
-
if (numGlyphs == 0 || text == NULL) {
return;
}
@@ -357,14 +389,18 @@
static RenderGlyph gRenderGlyph[] = {
&android::uirenderer::Font::drawCachedGlyph,
+ &android::uirenderer::Font::drawCachedGlyphPerspective,
&android::uirenderer::Font::drawCachedGlyphBitmap,
+ &android::uirenderer::Font::drawCachedGlyphBitmap,
+ &android::uirenderer::Font::measureCachedGlyph,
&android::uirenderer::Font::measureCachedGlyph
};
- RenderGlyph render = gRenderGlyph[mode];
+ RenderGlyph render = gRenderGlyph[(mode << 1) + mTransform.isPerspective()];
text += start;
int glyphsCount = 0;
+ const bool applyTransform = !mTransform.isIdentity() && !mTransform.isPerspective();
const SkPaint::Align align = paint->getTextAlign();
while (glyphsCount < numGlyphs) {
@@ -377,12 +413,13 @@
CachedGlyphInfo* cachedGlyph = getCachedGlyph(paint, glyph);
- // If it's still not valid, we couldn't cache it, so we shouldn't draw garbage
- if (cachedGlyph->mIsValid) {
+ // If it's still not valid, we couldn't cache it, so we shouldn't
+ // draw garbage; also skip empty glyphs (spaces)
+ if (cachedGlyph->mIsValid && cachedGlyph->mCacheTexture) {
float penX = x + positions[(glyphsCount << 1)];
float penY = y + positions[(glyphsCount << 1) + 1];
- if (!mTransform.isIdentity()) {
+ if (applyTransform) {
mTransform.mapPoint(penX, penY);
}
@@ -424,15 +461,18 @@
glyph->mBitmapWidth = skiaGlyph.fWidth;
glyph->mBitmapHeight = skiaGlyph.fHeight;
- uint32_t cacheWidth = glyph->mCacheTexture->getWidth();
- uint32_t cacheHeight = glyph->mCacheTexture->getHeight();
+ bool empty = skiaGlyph.fWidth == 0 || skiaGlyph.fHeight == 0;
+ if (!empty) {
+ uint32_t cacheWidth = glyph->mCacheTexture->getWidth();
+ uint32_t cacheHeight = glyph->mCacheTexture->getHeight();
- glyph->mBitmapMinU = startX / (float) cacheWidth;
- glyph->mBitmapMinV = startY / (float) cacheHeight;
- glyph->mBitmapMaxU = endX / (float) cacheWidth;
- glyph->mBitmapMaxV = endY / (float) cacheHeight;
+ glyph->mBitmapMinU = startX / (float) cacheWidth;
+ glyph->mBitmapMinV = startY / (float) cacheHeight;
+ glyph->mBitmapMaxU = endX / (float) cacheWidth;
+ glyph->mBitmapMaxV = endY / (float) cacheHeight;
- mState->setTextureDirty();
+ mState->setTextureDirty();
+ }
}
CachedGlyphInfo* Font::cacheGlyph(SkPaint* paint, glyph_t glyph, bool precaching) {
@@ -440,8 +480,8 @@
mCachedGlyphs.add(glyph, newGlyph);
const SkGlyph& skiaGlyph = GET_METRICS(paint, glyph, &mDescription.mLookupTransform);
- newGlyph->mGlyphIndex = skiaGlyph.fID;
newGlyph->mIsValid = false;
+ newGlyph->mGlyphIndex = skiaGlyph.fID;
updateGlyphCache(paint, skiaGlyph, newGlyph, precaching);
@@ -452,14 +492,13 @@
FontDescription description(paint, matrix);
Font* font = state->mActiveFonts.get(description);
- if (font) {
- font->mTransform.load(matrix);
- return font;
+ if (!font) {
+ font = new Font(state, description);
+ state->mActiveFonts.put(description, font);
}
+ font->mTransform.load(matrix);
- Font* newFont = new Font(state, description);
- state->mActiveFonts.put(description, newFont);
- return newFont;
+ return font;
}
}; // namespace uirenderer