michael@0: 
michael@0: /*
michael@0:  * Copyright 2011 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: #ifndef SkLineClipper_DEFINED
michael@0: #define SkLineClipper_DEFINED
michael@0: 
michael@0: #include "SkRect.h"
michael@0: #include "SkPoint.h"
michael@0: 
michael@0: class SkLineClipper {
michael@0: public:
michael@0:     enum {
michael@0:         kMaxPoints = 4,
michael@0:         kMaxClippedLineSegments = kMaxPoints - 1
michael@0:     };
michael@0: 
michael@0:     /*  Clip the line pts[0]...pts[1] against clip, ignoring segments that
michael@0:         lie completely above or below the clip. For portions to the left or
michael@0:         right, turn those into vertical line segments that are aligned to the
michael@0:         edge of the clip.
michael@0: 
michael@0:         Return the number of line segments that result, and store the end-points
michael@0:         of those segments sequentially in lines as follows:
michael@0:             1st segment: lines[0]..lines[1]
michael@0:             2nd segment: lines[1]..lines[2]
michael@0:             3rd segment: lines[2]..lines[3]
michael@0:      */
michael@0:     static int ClipLine(const SkPoint pts[2], const SkRect& clip,
michael@0:                         SkPoint lines[kMaxPoints]);
michael@0: 
michael@0:     /*  Intersect the line segment against the rect. If there is a non-empty
michael@0:         resulting segment, return true and set dst[] to that segment. If not,
michael@0:         return false and ignore dst[].
michael@0: 
michael@0:         ClipLine is specialized for scan-conversion, as it adds vertical
michael@0:         segments on the sides to show where the line extended beyond the
michael@0:         left or right sides. IntersectLine does not.
michael@0:      */
michael@0:     static bool IntersectLine(const SkPoint src[2], const SkRect& clip,
michael@0:                               SkPoint dst[2]);
michael@0: };
michael@0: 
michael@0: #endif