Implement touch control

tools/viewer/Viewer.cpp

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #include "Viewer.h"
 
 #include "GMSlide.h"
@@ skipping 84 matching lines @@
         }
         this->setupCurrentSlide(previousSlide);
     });
     fCommands.addCommand(Window::Key::kUp, "Up", "Transform", "Zoom in", [this]() {
         this->changeZoomLevel(1.f / 32.f);
         fWindow->inval();
     });
     fCommands.addCommand(Window::Key::kDown, "Down", "Transform", "Zoom out", [this]() {
         this->changeZoomLevel(-1.f / 32.f);
         fWindow->inval();
     });

[djsollen, 2016/05/17 12:40:25]

It seems more natural to me to implement the touch logic and SkTouchGesture
logic here.

 
     // set up slides
     this->initSlides();
 
     fAnimTimer.run();
 
     // set up first frame
     fCurrentSlide = 0;
     setupCurrentSlide(-1);
-    updateMatrix();
 
     fWindow->show();
 }
 
 void Viewer::initSlides() {
     const skiagm::GMRegistry* gms(skiagm::GMRegistry::Head());
     while (gms) {
         SkAutoTDelete<skiagm::GM> gm(gms->factory()(nullptr));
 
         if (!SkCommandLineFlags::ShouldSkip(FLAGS_match, gm->getName())) {
@@ skipping 72 matching lines @@
     fZoomLevel += delta;
     if (fZoomLevel > 0) {
         fZoomLevel = SkMinScalar(fZoomLevel, MAX_ZOOM_LEVEL);
         fZoomScale = fZoomLevel + SK_Scalar1;
     } else if (fZoomLevel < 0) {
         fZoomLevel = SkMaxScalar(fZoomLevel, MIN_ZOOM_LEVEL);
         fZoomScale = SK_Scalar1 / (SK_Scalar1 - fZoomLevel);
     } else {
         fZoomScale = SK_Scalar1;
     }
-    this->updateMatrix();
 }
 
-void Viewer::updateMatrix(){
+SkMatrix Viewer::computeMatrix() {
     SkMatrix m;
     m.reset();
 
     if (fZoomLevel) {
         SkPoint center;
         //m = this->getLocalMatrix();//.invert(&m);
         m.mapXY(fZoomCenterX, fZoomCenterY, &center);
         SkScalar cx = center.fX;
         SkScalar cy = center.fY;
 
         m.setTranslate(-cx, -cy);
         m.postScale(fZoomScale, fZoomScale);
         m.postTranslate(cx, cy);
     }
 
-    // TODO: add gesture support
-    // Apply any gesture matrix
-    //m.preConcat(fGesture.localM());
-    //m.preConcat(fGesture.globalM());
+    m.preConcat(fWindow->getGestureLocalM());
+    m.preConcat(fWindow->getGestureGlobalM());
 
-    fLocalMatrix = m;
+    return m;
 }
 
 void Viewer::onPaint(SkCanvas* canvas) {
 
     int count = canvas->save();
 
     if (fWindow->supportsContentRect()) {
         SkRect contentRect = fWindow->getContentRect();
         canvas->clipRect(contentRect);
         canvas->translate(contentRect.fLeft, contentRect.fTop);
     }
 
     canvas->clear(SK_ColorWHITE);
     if (fWindow->supportsContentRect() && fWindow->scaleContentToFit()) {
         const SkRect contentRect = fWindow->getContentRect();
         const SkISize slideSize = fSlides[fCurrentSlide]->getDimensions();
         const SkRect slideBounds = SkRect::MakeIWH(slideSize.width(), slideSize.height());
         SkMatrix matrix;
         matrix.setRectToRect(slideBounds, contentRect, SkMatrix::kCenter_ScaleToFit);
         canvas->concat(matrix);
     }
-    canvas->concat(fLocalMatrix);
+    canvas->concat(computeMatrix());
 
     fSlides[fCurrentSlide]->draw(canvas);
     canvas->restoreToCount(count);
 
     if (fDisplayStats) {
         drawStats(canvas);
     }
     fCommands.drawHelp(canvas);
 }
 
@@ skipping 49 matching lines @@
     // Record measurements
     fMeasurements[fCurrentMeasurement++] = ms;
     fCurrentMeasurement &= (kMeasurementCount - 1);  // fast mod
     SkASSERT(fCurrentMeasurement < kMeasurementCount);
 
     fAnimTimer.updateTime();
     if (fSlides[fCurrentSlide]->animate(fAnimTimer) || fDisplayStats) {
         fWindow->inval();
     }
 }