1 2 /* 3 * Copyright 2011 Google Inc. 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 #ifndef SkLineClipper_DEFINED 9 #define SkLineClipper_DEFINED 10 11 #include "SkRect.h" 12 #include "SkPoint.h" 13 14 class SkLineClipper { 15 public: 16 enum { 17 kMaxPoints = 4, 18 kMaxClippedLineSegments = kMaxPoints - 1 19 }; 20 21 /* Clip the line pts[0]...pts[1] against clip, ignoring segments that 22 lie completely above or below the clip. For portions to the left or 23 right, turn those into vertical line segments that are aligned to the 24 edge of the clip. 25 26 Return the number of line segments that result, and store the end-points 27 of those segments sequentially in lines as follows: 28 1st segment: lines[0]..lines[1] 29 2nd segment: lines[1]..lines[2] 30 3rd segment: lines[2]..lines[3] 31 */ 32 static int ClipLine(const SkPoint pts[2], const SkRect& clip, 33 SkPoint lines[kMaxPoints]); 34 35 /* Intersect the line segment against the rect. If there is a non-empty 36 resulting segment, return true and set dst[] to that segment. If not, 37 return false and ignore dst[]. 38 39 ClipLine is specialized for scan-conversion, as it adds vertical 40 segments on the sides to show where the line extended beyond the 41 left or right sides. IntersectLine does not. 42 */ 43 static bool IntersectLine(const SkPoint src[2], const SkRect& clip, 44 SkPoint dst[2]); 45 }; 46 47 #endif 48
