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/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkRSXform_DEFINED
#define SkRSXform_DEFINED
#include "SkPoint.h"
#include "SkSize.h"
/**
* A compressed form of a rotation+scale matrix.
*
* [ fSCos -fSSin fTx ]
* [ fSSin fSCos fTy ]
* [ 0 0 1 ]
*/
struct SkRSXform {
static SkRSXform Make(SkScalar scos, SkScalar ssin, SkScalar tx, SkScalar ty) {
SkRSXform xform = { scos, ssin, tx, ty };
return xform;
}
/*
* Initialize a new xform based on the scale, rotation (in radians), final tx,ty location
* and anchor-point ax,ay within the src quad.
*
* Note: the anchor point is not normalized (e.g. 0...1) but is in pixels of the src image.
*/
static SkRSXform MakeFromRadians(SkScalar scale, SkScalar radians, SkScalar tx, SkScalar ty,
SkScalar ax, SkScalar ay) {
const SkScalar s = SkScalarSin(radians) * scale;
const SkScalar c = SkScalarCos(radians) * scale;
return Make(c, s, tx + -c * ax + s * ay, ty + -s * ax - c * ay);
}
SkScalar fSCos;
SkScalar fSSin;
SkScalar fTx;
SkScalar fTy;
bool rectStaysRect() const {
return 0 == fSCos || 0 == fSSin;
}
void setIdentity() {
fSCos = 1;
fSSin = fTx = fTy = 0;
}
void set(SkScalar scos, SkScalar ssin, SkScalar tx, SkScalar ty) {
fSCos = scos;
fSSin = ssin;
fTx = tx;
fTy = ty;
}
void toQuad(SkScalar width, SkScalar height, SkPoint quad[4]) const;
void toQuad(const SkSize& size, SkPoint quad[4]) const {
this->toQuad(size.width(), size.height(), quad);
}
void toTriStrip(SkScalar width, SkScalar height, SkPoint strip[4]) const;
};
#endif
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