add localToGlobal and parents



git-svn-id: http://skia.googlecode.com/svn/trunk@511 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/utils/SkLayer.h b/include/utils/SkLayer.h
index c97bf72..c8dea48 100644
--- a/include/utils/SkLayer.h
+++ b/include/utils/SkLayer.h
@@ -53,11 +53,54 @@
 
     // children
 
+    /** Return the number of layers in our child list.
+     */
     int countChildren() const;
+
+    /** Return the child at the specified index (starting at 0). This does not
+        affect the reference count of the child.
+     */
     SkLayer* getChild(int index) const;
+
+    /** Add this layer to our child list at the end (top-most), and ref() it.
+        If it was already in another hierarchy, remove it from that list.
+        Return the new child.
+     */
     SkLayer* addChild(SkLayer* child);
+
+    /** Remove this layer from our child list, and unref() it and return true.
+        If it is not in our child list, do nothing and return false.
+     */
+    bool removeChild(SkLayer* child);
+
+    /** Remove, and unref(), all of the layers in our child list.
+     */
     void removeChildren();
 
+    /** Return our parent layer, or NULL if we have none.
+     */
+    SkLayer* getParent() const { return fParent; }
+
+    /** Return the root layer in this hiearchy. If this layer is the root
+        (i.e. has no parent), then this returns itself.
+     */
+    SkLayer* getRootLayer() const;
+
+    // coordinate system transformations
+
+    /** Return, in matrix, the matix transfomations that are applied locally
+        when this layer draws (i.e. its position and matrix/anchorPoint).
+        This does not include the childrenMatrix, since that is only applied
+        after this layer draws (but before its children draw).
+     */
+    void getLocalTransform(SkMatrix* matrix) const;
+
+    /** Return, in matrix, the concatenation of transforms that are applied
+        from this layer's root parent to the layer itself.
+        This is the matrix that is applied to the layer during drawing.
+     */
+    void localToGlobal(SkMatrix* matrix) const;
+
     // paint method
 
     void draw(SkCanvas*, SkScalar opacity);
@@ -69,6 +112,7 @@
     virtual void onDraw(SkCanvas*, SkScalar opacity);
 
 private:
+    SkLayer*    fParent;
     SkScalar    m_opacity;
     SkSize      m_size;
     SkPoint     m_position;
diff --git a/samplecode/SampleSkLayer.cpp b/samplecode/SampleSkLayer.cpp
index 8b6897b..c10bdfd 100644
--- a/samplecode/SampleSkLayer.cpp
+++ b/samplecode/SampleSkLayer.cpp
@@ -54,6 +54,24 @@
     
 ///////////////////////////////////////////////////////////////////////////////
 
+static void dump_layers(const SkLayer* layer, int tab = 0) {
+    SkMatrix matrix;
+    SkString matrixStr;
+
+    layer->getLocalTransform(&matrix);
+    matrix.toDumpString(&matrixStr);
+
+    for (int j = 0; j < tab; j++) {
+        SkDebugf(" ");
+    }
+    SkDebugf("layer=%p parent=%p size=[%g %g] transform=%s\n",
+             layer, layer->getParent(), layer->getWidth(), layer->getHeight(),
+             matrixStr.c_str());
+    for (int i = 0; i < layer->countChildren(); i++) {
+        dump_layers(layer->getChild(i), tab + 4);
+    }
+}
+
 class TestLayer : public SkLayer {
 public:
     TestLayer(SkColor c) : fColor(c) {}
@@ -77,7 +95,7 @@
 class SkLayerView : public SkView {
 private:
     SkLayer* fRootLayer;
-
+    SkLayer* fLastChild;
 public:
 	SkLayerView() {
         test44();
@@ -115,7 +133,16 @@
             m.setRotate(SkIntToScalar(30));
             child->setMatrix(m);
         }
+        fLastChild = child;
         fRootLayer->addChild(child)->unref();
+        
+        if (false) {
+            SkMatrix matrix;
+            matrix.setScale(0.5, 0.5);
+            fRootLayer->setMatrix(matrix);
+        }
+
+        dump_layers(fRootLayer);
     }
     
     virtual ~SkLayerView() {
@@ -132,17 +159,25 @@
         return this->INHERITED::onQuery(evt);
     }
     
-    void drawBG(SkCanvas* canvas) {
+    virtual void onDraw(SkCanvas* canvas) {
         canvas->drawColor(SK_ColorWHITE);
-
+        
         canvas->translate(20, 20);
         fRootLayer->draw(canvas);
+        
+        // visual test of getLocalTransform
+        if (true) {
+            SkMatrix matrix;
+            fLastChild->localToGlobal(&matrix);
+            SkPaint paint;
+            paint.setStyle(SkPaint::kStroke_Style);
+            paint.setStrokeWidth(5);
+            paint.setColor(0x88FF0000);
+            canvas->concat(matrix);
+            canvas->drawRect(SkRect::MakeSize(fLastChild->getSize()), paint);
+        }
     }
     
-    virtual void onDraw(SkCanvas* canvas) {
-        this->drawBG(canvas);
-}
-    
 private:
     typedef SkView INHERITED;
 };
diff --git a/src/utils/SkLayer.cpp b/src/utils/SkLayer.cpp
index 759f826..fe61c02 100644
--- a/src/utils/SkLayer.cpp
+++ b/src/utils/SkLayer.cpp
@@ -1,9 +1,17 @@
 #include "SkLayer.h"
 #include "SkCanvas.h"
 
-//#define DEBUG_LAYER_BOUNDS
+//#define DEBUG_DRAW_LAYER_BOUNDS
+//#define DEBUG_TRACK_NEW_DELETE
+
+#ifdef DEBUG_TRACK_NEW_DELETE
+    static int gLayerAllocCount;
+#endif
+
+///////////////////////////////////////////////////////////////////////////////
 
 SkLayer::SkLayer() {
+    fParent = NULL;
     m_opacity = SK_Scalar1;
     m_size.set(0, 0);
     m_position.set(0, 0);
@@ -11,9 +19,15 @@
 
     fMatrix.reset();
     fChildrenMatrix.reset();
+
+#ifdef DEBUG_TRACK_NEW_DELETE
+    gLayerAllocCount += 1;
+    SkDebugf("SkLayer new:    %d\n", gLayerAllocCount);
+#endif
 }
 
 SkLayer::SkLayer(const SkLayer& src) {
+    fParent = NULL;
     m_opacity = src.m_opacity;
     m_size = src.m_size;
     m_position = src.m_position;
@@ -21,12 +35,34 @@
 
     fMatrix = src.fMatrix;
     fChildrenMatrix = src.fChildrenMatrix;
+
+#ifdef DEBUG_TRACK_NEW_DELETE
+    gLayerAllocCount += 1;
+    SkDebugf("SkLayer copy:   %d\n", gLayerAllocCount);
+#endif
 }
 
 SkLayer::~SkLayer() {
     this->removeChildren();
+
+#ifdef DEBUG_TRACK_NEW_DELETE
+    gLayerAllocCount -= 1;
+    SkDebugf("SkLayer delete: %d\n", gLayerAllocCount);
+#endif
 }
 
+///////////////////////////////////////////////////////////////////////////////
+
+void SkLayer::setMatrix(const SkMatrix& matrix) {
+    fMatrix = matrix;
+}
+
+void SkLayer::setChildrenMatrix(const SkMatrix& matrix) {
+    fChildrenMatrix = matrix;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
 int SkLayer::countChildren() const {
     return m_children.count();
 }
@@ -40,23 +76,65 @@
 
 SkLayer* SkLayer::addChild(SkLayer* child) {
     child->ref();
+    if (child->fParent) {
+        child->fParent->removeChild(child);
+    }
+    SkASSERT(child->fParent == NULL);
+    child->fParent = this;
+
     *m_children.append() = child;
     return child;
 }
 
+bool SkLayer::removeChild(SkLayer* child) {
+    int index = m_children.find(child);
+    if (index >= 0) {
+        SkASSERT(child->fParent == this);
+        child->fParent = NULL;
+        child->unref();
+        m_children.remove(index);
+        return true;
+    }
+    return false;
+}
+
 void SkLayer::removeChildren() {
     m_children.unrefAll();
     m_children.reset();
 }
 
-///////////////////////////////////////////////////////////////////////////////
-
-void SkLayer::setMatrix(const SkMatrix& matrix) {
-    fMatrix = matrix;
+SkLayer* SkLayer::getRootLayer() const {
+    const SkLayer* root = this;
+    while (root->fParent != NULL) {
+        root = root->fParent;
+    }
+    return const_cast<SkLayer*>(root);
 }
 
-void SkLayer::setChildrenMatrix(const SkMatrix& matrix) {
-    fChildrenMatrix = matrix;
+///////////////////////////////////////////////////////////////////////////////
+
+void SkLayer::getLocalTransform(SkMatrix* matrix) const {
+    matrix->setTranslate(m_position.fX, m_position.fY);
+    
+    SkScalar tx = SkScalarMul(m_anchorPoint.fX, m_size.width());
+    SkScalar ty = SkScalarMul(m_anchorPoint.fY, m_size.height());
+    matrix->preTranslate(tx, ty);
+    matrix->preConcat(this->getMatrix());
+    matrix->preTranslate(-tx, -ty);
+}
+
+void SkLayer::localToGlobal(SkMatrix* matrix) const {
+    this->getLocalTransform(matrix);
+
+    const SkLayer* layer = this;
+    while (layer->fParent != NULL) {
+        layer = layer->fParent;
+
+        SkMatrix tmp;
+        layer->getLocalTransform(&tmp);
+        tmp.preConcat(layer->getChildrenMatrix());
+        matrix->postConcat(tmp);
+    }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -88,15 +166,12 @@
 
     SkAutoCanvasRestore acr(canvas, true);
 
-    // update the matrix
+    // apply our local transform
     {
-        SkScalar tx = m_position.fX;
-        SkScalar ty = m_position.fY;
-        canvas->translate(tx, ty);
+        canvas->translate(m_position.fX, m_position.fY);
         
-        // now apply our matrix about the anchorPoint
-        tx = SkScalarMul(m_anchorPoint.fX, m_size.width());
-        ty = SkScalarMul(m_anchorPoint.fY, m_size.height());
+        SkScalar tx = SkScalarMul(m_anchorPoint.fX, m_size.width());
+        SkScalar ty = SkScalarMul(m_anchorPoint.fY, m_size.height());
         canvas->translate(tx, ty);
         canvas->concat(this->getMatrix());
         canvas->translate(-tx, -ty);
@@ -104,7 +179,7 @@
 
     this->onDraw(canvas, opacity);
 
-#ifdef DEBUG_LAYER_BOUNDS
+#ifdef DEBUG_DRAW_LAYER_BOUNDS
     {
         SkRect r = SkRect::MakeSize(this->getSize());
         SkPaint p;