[WIP] Add Context to SkDrawLooper.

SkDrawLooper carries some state during draws. This CL extracts this state into
a separate class Context, which is then passed by the users of SkDrawLooper
into the appropriate methods.
This is a step towards making SkDrawLooper immutable.

BUG=skia:2141
R=scroggo@google.com, reed@google.com, sugoi@google.com

Author: dominikg@chromium.org

Review URL: https://codereview.chromium.org/155513012

git-svn-id: http://skia.googlecode.com/svn/trunk@13760 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 11 insertions, 6 deletions

diff --git a/src/core/SkDrawLooper.cpp b/src/core/SkDrawLooper.cpp
index bac2d969c0..c620cd08da 100644
--- a/src/core/SkDrawLooper.cpp
+++ b/src/core/SkDrawLooper.cpp
@@ -10,14 +10,17 @@
 #include "SkMatrix.h"
 #include "SkPaint.h"
 #include "SkRect.h"
+#include "SkSmallAllocator.h"
 
-bool SkDrawLooper::canComputeFastBounds(const SkPaint& paint) {
+bool SkDrawLooper::canComputeFastBounds(const SkPaint& paint) const {
     SkCanvas canvas;
+    SkSmallAllocator<1, 32> allocator;
+    void* buffer = allocator.reserveT<SkDrawLooper::Context>(this->contextSize());
 
-    this->init(&canvas);
+    SkDrawLooper::Context* context = this->createContext(&canvas, buffer);
     for (;;) {
         SkPaint p(paint);
-        if (this->next(&canvas, &p)) {
+        if (context->next(&canvas, &p)) {
             p.setLooper(NULL);
             if (!p.canComputeFastBounds()) {
                 return false;
@@ -30,14 +33,16 @@ bool SkDrawLooper::canComputeFastBounds(const SkPaint& paint) {
 }
 
 void SkDrawLooper::computeFastBounds(const SkPaint& paint, const SkRect& src,
-                                     SkRect* dst) {
+                                     SkRect* dst) const {
     SkCanvas canvas;
+    SkSmallAllocator<1, 32> allocator;
+    void* buffer = allocator.reserveT<SkDrawLooper::Context>(this->contextSize());
 
     *dst = src;   // catch case where there are no loops
-    this->init(&canvas);
+    SkDrawLooper::Context* context = this->createContext(&canvas, buffer);
     for (bool firstTime = true;; firstTime = false) {
         SkPaint p(paint);
-        if (this->next(&canvas, &p)) {
+        if (context->next(&canvas, &p)) {
             SkRect r(src);
 
             p.setLooper(NULL);