Require glyph positions in SkAtlasTextTarget::drawText

Change-Id: Idf0977befc8ed4fd9eb3b733db5e945457b2164c
Reviewed-on: https://skia-review.googlesource.com/73701
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

1 files changed, 17 insertions, 5 deletions

diff --git a/gm/atlastext.cpp b/gm/atlastext.cpp
index 8270306e5e..6ee092b49f 100644
--- a/gm/atlastext.cpp
+++ b/gm/atlastext.cpp
@@ -25,19 +25,31 @@
 
 static SkScalar draw_string(SkAtlasTextTarget* target, const SkString& text, SkScalar x, SkScalar y,
                             uint32_t color, sk_sp<SkTypeface> typeface, float size) {
+    if (!text.size()) {
+        return x;
+    }
     auto font = SkAtlasTextFont::Make(typeface, size);
     int cnt = SkUTF8_CountUnichars(text.c_str());
     std::unique_ptr<SkGlyphID[]> glyphs(new SkGlyphID[cnt]);
     typeface->charsToGlyphs(text.c_str(), SkTypeface::Encoding::kUTF8_Encoding, glyphs.get(), cnt);
 
-    target->drawText(glyphs.get(), cnt, x, y, color, *font);
-
-    // Using a paint just to perform a measure to let the caller know how much space to skip in x.
+    // Using a paint to get the positions for each glyph.
     SkPaint paint;
     paint.setTextSize(size);
     paint.setTypeface(std::move(typeface));
-    paint.setTextEncoding(SkPaint::kUTF8_TextEncoding);
-    return x + paint.measureText(text.c_str(), text.size());
+    paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
+    std::unique_ptr<SkScalar[]> widths(new SkScalar[cnt]);
+    paint.getTextWidths(glyphs.get(), cnt * sizeof(SkGlyphID), widths.get(), nullptr);
+
+    std::unique_ptr<SkPoint[]> positions(new SkPoint[cnt]);
+    positions[0] = {x, y};
+    for (int i = 1; i < cnt; ++i) {
+        positions[i] = {positions[i - 1].fX + widths[i - 1], y};
+    }
+
+    target->drawText(glyphs.get(), positions.get(), cnt, color, *font);
+
+    return positions[cnt - 1].fX + widths[cnt - 1];
 }
 
 class AtlasTextGM : public skiagm::GM {