SkPaint intercept API for SkTextBlob and horizontal text

src/core/SkPaint.cpp

Index: src/core/SkPaint.cpp
diff --git a/src/core/SkPaint.cpp b/src/core/SkPaint.cpp
index 528b1d0404507fb484ab1da564bf716f7e2a8181..07c10d5a78cd4a0a9ee8b583ffe559f38ac44130 100644
--- a/src/core/SkPaint.cpp
+++ b/src/core/SkPaint.cpp
@@ -27,12 +27,14 @@
 #include "SkShader.h"
 #include "SkStringUtils.h"
 #include "SkStroke.h"
+#include "SkStrokeRec.h"
+#include "SkSurfacePriv.h"
+#include "SkTextBlob.h"
+#include "SkTextBlobRunIterator.h"
 #include "SkTextFormatParams.h"
 #include "SkTextToPathIter.h"
 #include "SkTLazy.h"
 #include "SkTypeface.h"
-#include "SkStrokeRec.h"
-#include "SkSurfacePriv.h"
 #include "SkXfermode.h"
 
 static inline uint32_t set_clear_mask(uint32_t bits, bool cond, uint32_t mask) {
@@ -1127,23 +1129,6 @@ void SkPaint::getTextPath(const void* textData, size_t length,
     }
 }
 
-int SkPaint::getTextIntercepts(const void* textData, size_t length,
-                               SkScalar x, SkScalar y, const SkScalar bounds[2],
-                               SkScalar* array) const {
-    SkASSERT(length == 0 || textData != nullptr);
-    if (!length) {
-        return 0;
-    }
-
-    const char* text = (const char*) textData;
-    SkTextInterceptsIter iter(text, length, *this, bounds, x, y,
-            SkTextInterceptsIter::TextType::kText);
-    int count = 0;
-    while (iter.next(array, &count)) {
-    }
-    return count;
-}
-
 void SkPaint::getPosTextPath(const void* textData, size_t length,
                              const SkPoint pos[], SkPath* path) const {
     SkASSERT(length == 0 || textData != nullptr);
@@ -1173,22 +1158,89 @@ void SkPaint::getPosTextPath(const void* textData, size_t length,
     }
 }
 
-int SkPaint::getPosTextIntercepts(const void* textData, size_t length, const SkPoint pos[],
-                                  const SkScalar bounds[2], SkScalar* array) const {
-    SkASSERT(length == 0 || textData != nullptr);
+template <SkTextInterceptsIter::TextType TextType, typename Func>
+int GetTextIntercepts(const SkPaint& paint, const void* text, size_t length,
+                      const SkScalar bounds[2], SkScalar* array, Func posMaker) {
+    SkASSERT(length == 0 || text != nullptr);
     if (!length) {
         return 0;
     }
 
-    const char* text = (const char*) textData;
-    SkTextInterceptsIter iter(text, length, *this, bounds, pos[0].fX, pos[0].fY,
-            SkTextInterceptsIter::TextType::kPosText);
+    const SkPoint pos0 = posMaker(0);
+    SkTextInterceptsIter iter(static_cast<const char*>(text), length, paint, bounds,
+                              pos0.x(), pos0.y(), TextType);
+
     int i = 0;
     int count = 0;
     while (iter.next(array, &count)) {
-        i++;
-        iter.setPosition(pos[i].fX, pos[i].fY);
+        if (TextType == SkTextInterceptsIter::TextType::kPosText) {
+            const SkPoint pos = posMaker(++i);
+            iter.setPosition(pos.x(), pos.y());
+        }
+    }
+
+    return count;
+}
+
+int SkPaint::getTextIntercepts(const void* textData, size_t length,
+                               SkScalar x, SkScalar y, const SkScalar bounds[2],
+                               SkScalar* array) const {
+
+    return GetTextIntercepts<SkTextInterceptsIter::TextType::kText>(
+        *this, textData, length, bounds, array, [&x, &y] (int) -> SkPoint {
+            return SkPoint::Make(x, y);
+        });
+}
+
+int SkPaint::getPosTextIntercepts(const void* textData, size_t length, const SkPoint pos[],
+                                  const SkScalar bounds[2], SkScalar* array) const {
+
+    return GetTextIntercepts<SkTextInterceptsIter::TextType::kPosText>(
+        *this, textData, length, bounds, array, [&pos] (int i) -> SkPoint {
+            return pos[i];
+        });
+}
+
+int SkPaint::getPosTextHIntercepts(const void* textData, size_t length, const SkScalar xpos[],
+                                   SkScalar constY, const SkScalar bounds[2],
+                                   SkScalar* array) const {
+
+    return GetTextIntercepts<SkTextInterceptsIter::TextType::kPosText>(
+        *this, textData, length, bounds, array, [&xpos, &constY] (int i) -> SkPoint {
+            return SkPoint::Make(xpos[i], constY);
+        });
+}
+
+int SkPaint::getTextBlobIntercepts(const SkTextBlob* blob, const SkScalar bounds[2],
+                                   SkScalar* intervals) const {
+    int count = 0;
+    SkPaint runPaint(*this);
+
+    SkTextBlobRunIterator it(blob);
+    while (!it.done()) {
+        it.applyFontToPaint(&runPaint);
+        const size_t runByteCount = it.glyphCount() * sizeof(SkGlyphID);
+        SkScalar* runIntervals = intervals ? intervals + count : nullptr;
+
+        switch (it.positioning()) {
+        case SkTextBlob::kDefault_Positioning:
+            count += runPaint.getTextIntercepts(it.glyphs(), runByteCount, it.offset().x(),
+                                                it.offset().y(), bounds, runIntervals);
+            break;
+        case SkTextBlob::kHorizontal_Positioning:
+            count += runPaint.getPosTextHIntercepts(it.glyphs(), runByteCount, it.pos(),
+                                                    it.offset().y(), bounds, runIntervals);
+            break;
+        case SkTextBlob::kFull_Positioning:
+            count += runPaint.getPosTextIntercepts(it.glyphs(), runByteCount,
+                                                   reinterpret_cast<const SkPoint*>(it.pos()),
+                                                   bounds, runIntervals);
+            break;
+        }
+
+        it.next();
     }
+
     return count;
 }