SkPaint intercept API for SkTextBlob and horizontal text

include/core/SkPaint.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkPaint_DEFINED
 #define SkPaint_DEFINED
 
@@ skipping 15 matching lines @@
 class SkGlyphCache;
 class SkImageFilter;
 class SkMaskFilter;
 class SkPath;
 class SkPathEffect;
 struct SkPoint;
 class SkRasterizer;
 struct SkScalerContextEffects;
 class SkShader;
 class SkSurfaceProps;
+class SkTextBlob;
 class SkTypeface;
 
 #define kBicubicFilterBitmap_Flag kHighQualityFilterBitmap_Flag
 
 /** \class SkPaint
 
     The SkPaint class holds the style and color information about how to draw
     geometries, text and bitmaps.
 */
 class SK_API SkPaint {
@@ skipping 911 matching lines @@
      *  @param length       number of bytes of text
      *  @param pos          array of positions, used to position each character
      *  @param bounds       The lower and upper line parallel to the advance.
      *  @param array        If not null, the glyph bounds contained by the advance parallel lines.
      *
      *  @return             The number of intersections, which may be zero.
      */
     int getPosTextIntercepts(const void* text, size_t length, const SkPoint pos[],
                              const SkScalar bounds[2], SkScalar* intervals) const;
 
+    /** Return the number of intervals that intersect the intercept along the axis of the advance.
+     *  The return count is zero or a multiple of two, and is at most the number of glyphs * 2 in
+     *  string. The caller may pass nullptr for intervals to determine the size of the interval
+     *  array, or may conservatively pre-allocate an array with length * 2 entries. The computed
+     *  intervals are cached by glyph to improve performance for multiple calls.
+     *  This permits constructing an underline that skips the descenders.
+     *
+     *  @param text         The text.
+     *  @param length       Number of bytes of text.
+     *  @param xpos         Array of x-positions, used to position each character.
+     *  @param constY       The shared Y coordinate for all of the positions.
+     *  @param bounds       The lower and upper line parallel to the advance.
+     *  @param array        If not null, the glyph bounds contained by the advance parallel lines.
+     *
+     *  @return             The number of intersections, which may be zero.
+     */
+    int getPosTextHIntercepts(const void* text, size_t length, const SkScalar xpos[],
+                              SkScalar constY, const SkScalar bounds[2], SkScalar* intervals) const;
+
+    /** Return the number of intervals that intersect the intercept along the axis of the advance.
+     *  The return count is zero or a multiple of two, and is at most the number of glyphs * 2 in
+     *  text blob. The caller may pass nullptr for intervals to determine the size of the interval
+     *  array. The computed intervals are cached by glyph to improve performance for multiple calls.
+     *  This permits constructing an underline that skips the descenders.
+     *
+     *  @param blob         The text blob.
+     *  @param bounds       The lower and upper line parallel to the advance.
+     *  @param array        If not null, the glyph bounds contained by the advance parallel lines.
+     *
+     *  @return             The number of intersections, which may be zero.
+     */
+    int getTextBlobIntercepts(const SkTextBlob* blob, const SkScalar bounds[2],
+                              SkScalar* intervals) const;
+
     /**
      *  Return a rectangle that represents the union of the bounds of all
      *  of the glyphs, but each one positioned at (0,0). This may be conservatively large, and
      *  will not take into account any hinting, but will respect any text-scale-x or text-skew-x
      *  on this paint.
      */
     SkRect getFontBounds() const;
 
     // returns true if the paint's settings (e.g. xfermode + alpha) resolve to
     // mean that we need not draw at all (e.g. SrcOver + 0-alpha)
@@ skipping 197 matching lines @@
     friend class GrStencilAndCoverTextContext;
     friend class GrPathRendering;
     friend class GrTextUtils;
     friend class GrGLPathRendering;
     friend class SkScalerContext;
     friend class SkTextBaseIter;
     friend class SkCanonicalizePaint;
 };
 
 #endif