skia2/samplecode/SampleWarp.cpp
reed@android.com d2abab656b first cut at rubber-sheet warping
git-svn-id: http://skia.googlecode.com/svn/trunk@401 2bbb7eff-a529-9590-31e7-b0007b416f81
2009-10-20 21:27:15 +00:00

212 lines
6.0 KiB
C++

#include "SampleCode.h"
#include "SkView.h"
#include "SkCanvas.h"
#include "SkGradientShader.h"
#include "SkPath.h"
#include "SkRegion.h"
#include "SkShader.h"
#include "SkUtils.h"
#include "SkImageDecoder.h"
class Mesh {
public:
Mesh();
~Mesh();
Mesh& operator=(const Mesh& src);
void init(const SkRect& bounds, int rows, int cols,
const SkRect& texture);
int rows() const { return fRows; }
int cols() const { return fCols; }
SkPoint& pt(int row, int col) {
return fPts[row * (fRows + 1) + col];
}
void draw(SkCanvas*, const SkPaint&);
void drawWireframe(SkCanvas* canvas, const SkPaint& paint);
private:
int fRows, fCols;
SkPoint* fPts;
SkPoint* fTex; // just points into fPts, not separately allocated
int fCount;
uint16_t* fIndices;
int fIndexCount;
};
Mesh::Mesh() : fPts(NULL), fCount(0), fIndices(NULL), fIndexCount(0) {}
Mesh::~Mesh() {
delete[] fPts;
delete[] fIndices;
}
Mesh& Mesh::operator=(const Mesh& src) {
delete[] fPts;
delete[] fIndices;
fRows = src.fRows;
fCols = src.fCols;
fCount = src.fCount;
fPts = new SkPoint[fCount * 2];
fTex = fPts + fCount;
memcpy(fPts, src.fPts, fCount * 2 * sizeof(SkPoint));
delete[] fIndices;
fIndexCount = src.fIndexCount;
fIndices = new uint16_t[fIndexCount];
memcpy(fIndices, src.fIndices, fIndexCount * sizeof(uint16_t));
return *this;
}
void Mesh::init(const SkRect& bounds, int rows, int cols,
const SkRect& texture) {
SkASSERT(rows > 0 && cols > 0);
fRows = rows;
fCols = cols;
delete[] fPts;
fCount = (rows + 1) * (cols + 1);
fPts = new SkPoint[fCount * 2];
fTex = fPts + fCount;
delete[] fIndices;
fIndexCount = rows * cols * 6;
fIndices = new uint16_t[fIndexCount];
SkPoint* pts = fPts;
const SkScalar dx = bounds.width() / rows;
const SkScalar dy = bounds.height() / cols;
SkPoint* tex = fTex;
const SkScalar dtx = texture.width() / rows;
const SkScalar dty = texture.height() / cols;
uint16_t* idx = fIndices;
int index = 0;
for (int y = 0; y <= cols; y++) {
for (int x = 0; x <= rows; x++) {
pts->set(bounds.fLeft + x*dx, bounds.fTop + y*dy);
pts += 1;
tex->set(texture.fLeft + x*dtx, texture.fTop + y*dty);
tex += 1;
if (y < cols && x < rows) {
*idx++ = index;
*idx++ = index + rows + 1;
*idx++ = index + 1;
*idx++ = index + 1;
*idx++ = index + rows + 1;
*idx++ = index + rows + 2;
index += 1;
}
}
index += 1;
}
}
void Mesh::draw(SkCanvas* canvas, const SkPaint& paint) {
canvas->drawVertices(SkCanvas::kTriangles_VertexMode, fCount,
fPts, fTex, NULL, NULL, fIndices, fIndexCount,
paint);
}
void Mesh::drawWireframe(SkCanvas* canvas, const SkPaint& paint) {
canvas->drawVertices(SkCanvas::kTriangles_VertexMode, fCount,
fPts, NULL, NULL, NULL, fIndices, fIndexCount,
paint);
}
///////////////////////////////////////////////////////////////////////////////
class WarpView : public SkView {
Mesh fMesh, fOrig;
SkBitmap fBitmap;
public:
WarpView() {
SkBitmap bm;
SkImageDecoder::DecodeFile("/skimages/nytimes.png", &bm);
SkIRect subset = { 0, 0, 420, 420 };
bm.extractSubset(&fBitmap, subset);
SkRect bounds, texture;
texture.set(0, 0, SkIntToScalar(fBitmap.width()),
SkIntToScalar(fBitmap.height()));
bounds = texture;
// fMesh.init(bounds, fBitmap.width() / 40, fBitmap.height() / 40, texture);
fMesh.init(bounds, 10, 10, texture);
fOrig = fMesh;
}
protected:
// overrides from SkEventSink
virtual bool onQuery(SkEvent* evt) {
if (SampleCode::TitleQ(*evt)) {
SampleCode::TitleR(evt, "Warp");
return true;
}
return this->INHERITED::onQuery(evt);
}
void warp(const SkPoint& p0, const SkPoint& p1) {
int rows = fMesh.rows();
int cols = fMesh.cols();
const SkVector delta = p1 - p0;
for (int y = 1; y < cols; y++) {
for (int x = 1; x < rows; x++) {
const SkPoint& orig = fOrig.pt(x, y);
SkScalar dist = SkPoint::Distance(p0, orig);
dist += SkIntToScalar(1);
// dist = SkScalarSqrt(dist);
SkScalar dx = SkScalarDiv(delta.fX, dist);
SkScalar dy = SkScalarDiv(delta.fY, dist);
fMesh.pt(x, y).set(orig.fX + dx, orig.fY + dy);
// SkDebugf("[%g %g] -> [%d %d %g] <%g %g>\n", delta.fX, delta.fY, x, y, dist, dx, dy);
}
}
}
virtual void onDraw(SkCanvas* canvas) {
canvas->drawColor(SK_ColorGRAY);
SkPaint paint;
paint.setFilterBitmap(true);
paint.setShader(SkShader::CreateBitmapShader(fBitmap,
SkShader::kClamp_TileMode,
SkShader::kClamp_TileMode))->unref();
fMesh.draw(canvas, paint);
paint.setShader(NULL);
paint.setColor(SK_ColorRED);
fMesh.draw(canvas, paint);
}
virtual SkView::Click* onFindClickHandler(SkScalar x, SkScalar y) {
return new Click(this);
}
virtual bool onClick(Click* click) {
this->warp(click->fOrig, click->fCurr);
this->inval(NULL);
return true;
}
private:
SkIRect fBase, fRect;
typedef SkView INHERITED;
};
//////////////////////////////////////////////////////////////////////////////
static SkView* MyFactory() { return new WarpView; }
static SkViewRegister reg(MyFactory);