6b20a55996
Change-Id: Ice7d761b1023da77e50e5d6aa597964f7d9aa1d8 Reviewed-on: https://skia-review.googlesource.com/8302 Commit-Queue: Hal Canary <halcanary@google.com> Reviewed-by: Mike Reed <reed@google.com>
69 lines
1.8 KiB
C
69 lines
1.8 KiB
C
/*
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* Copyright 2015 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkRSXform_DEFINED
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#define SkRSXform_DEFINED
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#include "SkPoint.h"
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#include "SkSize.h"
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/**
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* A compressed form of a rotation+scale matrix.
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*
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* [ fSCos -fSSin fTx ]
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* [ fSSin fSCos fTy ]
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* [ 0 0 1 ]
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*/
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struct SkRSXform {
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static SkRSXform Make(SkScalar scos, SkScalar ssin, SkScalar tx, SkScalar ty) {
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SkRSXform xform = { scos, ssin, tx, ty };
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return xform;
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}
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/*
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* Initialize a new xform based on the scale, rotation (in radians), final tx,ty location
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* and anchor-point ax,ay within the src quad.
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*
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* Note: the anchor point is not normalized (e.g. 0...1) but is in pixels of the src image.
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*/
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static SkRSXform MakeFromRadians(SkScalar scale, SkScalar radians, SkScalar tx, SkScalar ty,
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SkScalar ax, SkScalar ay) {
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const SkScalar s = SkScalarSin(radians) * scale;
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const SkScalar c = SkScalarCos(radians) * scale;
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return Make(c, s, tx + -c * ax + s * ay, ty + -s * ax - c * ay);
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}
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SkScalar fSCos;
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SkScalar fSSin;
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SkScalar fTx;
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SkScalar fTy;
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bool rectStaysRect() const {
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return 0 == fSCos || 0 == fSSin;
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}
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void setIdentity() {
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fSCos = 1;
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fSSin = fTx = fTy = 0;
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}
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void set(SkScalar scos, SkScalar ssin, SkScalar tx, SkScalar ty) {
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fSCos = scos;
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fSSin = ssin;
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fTx = tx;
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fTy = ty;
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}
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void toQuad(SkScalar width, SkScalar height, SkPoint quad[4]) const;
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void toQuad(const SkSize& size, SkPoint quad[4]) const {
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this->toQuad(size.width(), size.height(), quad);
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}
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};
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#endif
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