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>

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 {

include/atlastext/SkAtlasTextTarget.h

@@ -14,6 +14,7 @@
 
 class SkAtlasTextContext;
 class SkAtlasTextFont;
+struct SkPoint;
 
 /** Represents a client-created renderable surface and is used to draw text into the surface. */
 class SK_API SkAtlasTextTarget {
@@ -28,11 +29,12 @@ public:
                                                    void* handle);
 
     /**
-     * Enqueues a text draw in the target. The meaning of 'color' here is interpreted by the
-     * client's SkAtlasTextRenderer when it actually renders the text.
+     * Enqueues a text draw in the target. The caller provides an array of glyphs and their
+     * positions. The meaning of 'color' here is interpreted by the client's SkAtlasTextRenderer
+     * when it actually renders the text.
      */
-    virtual void drawText(const SkGlyphID*, int glyphCnt, SkScalar x, SkScalar y, uint32_t color,
-                          const SkAtlasTextFont& font) = 0;
+    virtual void drawText(const SkGlyphID[], const SkPoint[], int glyphCnt, uint32_t color,
+                          const SkAtlasTextFont&) = 0;
 
     /** Issues all queued text draws to SkAtlasTextRenderer. */
     virtual void flush() = 0;

src/atlastext/SkAtlasTextTarget.cpp

@@ -7,6 +7,8 @@
 
 #include "SkAtlasTextTarget.h"
 #include "GrClip.h"
+#include "GrContextPriv.h"
+#include "GrDrawingManager.h"
 #include "SkAtlasTextContext.h"
 #include "SkAtlasTextFont.h"
 #include "SkAtlasTextRenderer.h"
@@ -50,7 +52,7 @@ public:
 
     /** SkAtlasTextTarget overrides */
 
-    void drawText(const SkGlyphID*, int glyphCnt, SkScalar x, SkScalar y, uint32_t color,
+    void drawText(const SkGlyphID[], const SkPoint[], int glyphCnt, uint32_t color,
                   const SkAtlasTextFont&) override;
     void flush() override;
 
@@ -75,11 +77,9 @@ std::unique_ptr<SkAtlasTextTarget> SkAtlasTextTarget::Make(sk_sp<SkAtlasTextCont
 
 //////////////////////////////////////////////////////////////////////////////
 
-#include "GrContextPriv.h"
-#include "GrDrawingManager.h"
-
-void SkInternalAtlasTextTarget::drawText(const SkGlyphID* glyphs, int glyphCnt, SkScalar x,
-                                         SkScalar y, uint32_t color, const SkAtlasTextFont& font) {
+void SkInternalAtlasTextTarget::drawText(const SkGlyphID glyphs[], const SkPoint positions[],
+                                         int glyphCnt, uint32_t color,
+                                         const SkAtlasTextFont& font) {
     SkPaint paint;
     paint.setAntiAlias(true);
     paint.setTypeface(font.refTypeface());
@@ -91,14 +91,14 @@ void SkInternalAtlasTextTarget::drawText(const SkGlyphID* glyphs, int glyphCnt,
     // and the context will write it into the final vertices given to the client's renderer.
     fColor = color;
 
-    // The pixel geometry here is arbitrary. We don't draw LCD text.
     SkSurfaceProps props(SkSurfaceProps::kUseDistanceFieldFonts_Flag, kUnknown_SkPixelGeometry);
     auto* grContext = this->context()->internal().grContext();
     auto bounds = SkIRect::MakeWH(fWidth, fHeight);
     auto atlasTextContext = grContext->contextPriv().drawingManager()->getAtlasTextContext();
     size_t byteLength = sizeof(SkGlyphID) * glyphCnt;
-    atlasTextContext->drawText(grContext, this, GrNoClip(), paint, SkMatrix::I(), props,
-                               (const char*)glyphs, byteLength, x, y, bounds);
+    const SkScalar* pos = &positions->fX;
+    atlasTextContext->drawPosText(grContext, this, GrNoClip(), paint, SkMatrix::I(), props,
+                                  (const char*)glyphs, byteLength, pos, 2, {0, 0}, bounds);
 }
 
 void SkInternalAtlasTextTarget::addDrawOp(const GrClip& clip, std::unique_ptr<GrAtlasTextOp> op) {