add clipstack to canvas. not used yet, but will be for devices (e.g. gpu) that
want to see how the clip was built
git-svn-id: http://skia.googlecode.com/svn/trunk@824 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkClipStack.cpp b/src/core/SkClipStack.cpp
new file mode 100644
index 0000000..2b63aea
--- /dev/null
+++ b/src/core/SkClipStack.cpp
@@ -0,0 +1,144 @@
+#include "SkClipStack.h"
+#include "SkPath.h"
+#include <new>
+
+struct SkClipStack::Rec {
+ enum State {
+ kEmpty_State,
+ kRect_State,
+ kPath_State
+ };
+
+ SkPath fPath;
+ SkRect fRect;
+ int fSaveCount;
+ SkRegion::Op fOp;
+ State fState;
+
+ Rec(int saveCount, const SkRect& rect, SkRegion::Op op) : fRect(rect) {
+ fSaveCount = saveCount;
+ fOp = op;
+ fState = kRect_State;
+ }
+
+ Rec(int saveCount, const SkPath& path, SkRegion::Op op) : fPath(path) {
+ fSaveCount = saveCount;
+ fOp = op;
+ fState = kPath_State;
+ }
+
+ /**
+ * Returns true if this Rec can be intersected in place with a new clip
+ */
+ bool canBeIntersected(int saveCount, SkRegion::Op op) const {
+ if (kEmpty_State == fState) {
+ return true;
+ }
+ return fSaveCount == saveCount &&
+ SkRegion::kIntersect_Op == fOp &&
+ SkRegion::kIntersect_Op == op;
+ }
+};
+
+SkClipStack::SkClipStack() : fDeque(sizeof(Rec)) {
+ fSaveCount = 0;
+}
+
+void SkClipStack::reset() {
+ // don't have a reset() on SkDeque, so fake it here
+ fDeque.~SkDeque();
+ new (&fDeque) SkDeque(sizeof(Rec));
+
+ fSaveCount = 0;
+}
+
+void SkClipStack::save() {
+ fSaveCount += 1;
+}
+
+void SkClipStack::restore() {
+ fSaveCount -= 1;
+ while (!fDeque.empty()) {
+ Rec* rec = (Rec*)fDeque.back();
+ if (rec->fSaveCount <= fSaveCount) {
+ break;
+ }
+ rec->~Rec();
+ fDeque.pop_back();
+ }
+}
+
+void SkClipStack::clipDevRect(const SkRect& rect, SkRegion::Op op) {
+ Rec* rec = (Rec*)fDeque.back();
+ if (rec && rec->canBeIntersected(fSaveCount, op)) {
+ switch (rec->fState) {
+ case Rec::kEmpty_State:
+ return;
+ case Rec::kRect_State:
+ if (!rec->fRect.intersect(rect)) {
+ rec->fState = Rec::kEmpty_State;
+ }
+ return;
+ case Rec::kPath_State:
+ if (!SkRect::Intersects(rec->fPath.getBounds(), rect)) {
+ rec->fState = Rec::kEmpty_State;
+ return;
+ }
+ break;
+ }
+ }
+ new (fDeque.push_back()) Rec(fSaveCount, rect, op);
+}
+
+void SkClipStack::clipDevPath(const SkPath& path, SkRegion::Op op) {
+ Rec* rec = (Rec*)fDeque.back();
+ if (rec && rec->canBeIntersected(fSaveCount, op)) {
+ const SkRect& pathBounds = path.getBounds();
+ switch (rec->fState) {
+ case Rec::kEmpty_State:
+ return;
+ case Rec::kRect_State:
+ if (!SkRect::Intersects(rec->fRect, pathBounds)) {
+ rec->fState = Rec::kEmpty_State;
+ return;
+ }
+ break;
+ case Rec::kPath_State:
+ if (!SkRect::Intersects(rec->fPath.getBounds(), pathBounds)) {
+ rec->fState = Rec::kEmpty_State;
+ return;
+ }
+ break;
+ }
+ }
+ new (fDeque.push_back()) Rec(fSaveCount, path, op);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+SkClipStack::B2FIter::B2FIter(const SkClipStack& stack) : fIter(stack.fDeque) {
+}
+
+const SkClipStack::B2FIter::Clip* SkClipStack::B2FIter::next() {
+ const SkClipStack::Rec* rec = (const SkClipStack::Rec*)fIter.next();
+ if (NULL == rec) {
+ return NULL;
+ }
+
+ switch (rec->fState) {
+ case SkClipStack::Rec::kEmpty_State:
+ fClip.fRect = NULL;
+ fClip.fPath = NULL;
+ break;
+ case SkClipStack::Rec::kRect_State:
+ fClip.fRect = &rec->fRect;
+ fClip.fPath = NULL;
+ break;
+ case SkClipStack::Rec::kPath_State:
+ fClip.fRect = NULL;
+ fClip.fPath = &rec->fPath;
+ break;
+ }
+ fClip.fOp = rec->fOp;
+ return &fClip;
+}