center glyphs for text-on-path-via-rsxform
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2137083005
Review-Url: https://codereview.chromium.org/2137083005
diff --git a/gm/drawatlas.cpp b/gm/drawatlas.cpp
index ca0e9b9..a98b176 100644
--- a/gm/drawatlas.cpp
+++ b/gm/drawatlas.cpp
@@ -110,56 +110,62 @@
SkPathMeasure meas(path, false);
int count = paint.countText(text, length);
- SkAutoSTArray<100, SkRSXform> xform(count);
+ size_t size = count * (sizeof(SkRSXform) + sizeof(SkScalar));
+ SkAutoSMalloc<512> storage(size);
+ SkRSXform* xform = (SkRSXform*)storage.get();
+ SkScalar* widths = (SkScalar*)(xform + count);
+
+ paint.getTextWidths(text, length, widths);
for (int i = 0; i < count; ++i) {
+ // we want to position each character on the center of its advance
+ const SkScalar offset = SkScalarHalf(widths[i]);
SkPoint pos;
SkVector tan;
- if (!meas.getPosTan(xy[i].x(), &pos, &tan)) {
+ if (!meas.getPosTan(xy[i].x() + offset, &pos, &tan)) {
pos = xy[i];
tan.set(1, 0);
}
xform[i].fSCos = tan.x();
xform[i].fSSin = tan.y();
- xform[i].fTx = pos.x() - tan.y() * xy[i].y();
- xform[i].fTy = pos.y() + tan.x() * xy[i].y();
+ xform[i].fTx = pos.x() - tan.y() * xy[i].y() - tan.x() * offset;
+ xform[i].fTy = pos.y() + tan.x() * xy[i].y() - tan.y() * offset;
}
- canvas->drawTextRSXform(text, length, &xform[0], nullptr, paint);
+ // Compute a conservative bounds so we can cull the draw
+ const SkRect font = paint.getFontBounds();
+ const SkScalar max = SkTMax(SkTMax(SkScalarAbs(font.fLeft), SkScalarAbs(font.fRight)),
+ SkTMax(SkScalarAbs(font.fTop), SkScalarAbs(font.fBottom)));
+ const SkRect bounds = path.getBounds().makeOutset(max, max);
+
+ canvas->drawTextRSXform(text, length, &xform[0], &bounds, paint);
+
+ if (true) {
+ SkPaint p;
+ p.setStyle(SkPaint::kStroke_Style);
+ canvas->drawRect(bounds, p);
+ }
}
-DEF_SIMPLE_GM(drawTextRSXform, canvas, 510, 370) {
+DEF_SIMPLE_GM(drawTextRSXform, canvas, 860, 860) {
const char text0[] = "ABCDFGHJKLMNOPQRSTUVWXYZ";
- const char text1[] = "AAAAAAAAAAAAAAAAAAAAAAAAAA";
const int N = sizeof(text0) - 1;
SkPoint pos[N];
- SkRSXform xform[N];
-
- canvas->translate(0, 30);
-
- SkScalar x = 20;
- SkScalar dx = 20;
- SkScalar rad = 0;
- SkScalar drad = 2 * SK_ScalarPI / (N - 1);
- for (int i = 0; i < N; ++i) {
- xform[i].fSCos = SkScalarCos(rad);
- xform[i].fSSin = SkScalarSin(rad);
- xform[i].fTx = x;
- xform[i].fTy = 0;
- pos[i].set(x, -10);
- x += dx;
- rad += drad;
- }
SkPaint paint;
paint.setAntiAlias(true);
- paint.setTextSize(20);
- canvas->drawTextRSXform(text0, N, xform, nullptr, paint);
+ paint.setTextSize(100);
+
+ SkScalar x = 0;
+ for (int i = 0; i < N; ++i) {
+ pos[i].set(x, 0);
+ x += paint.measureText(&text0[i], 1);
+ }
SkPath path;
- path.addOval(SkRect::MakeXYWH(150, 100, 200, 200));
+ path.addOval(SkRect::MakeXYWH(160, 160, 540, 540));
- draw_text_on_path_rigid(canvas, text1, N, pos, path, paint);
+ draw_text_on_path_rigid(canvas, text0, N, pos, path, paint);
paint.setStyle(SkPaint::kStroke_Style);
canvas->drawPath(path, paint);