SkDocument base for pdf, xps, etc.

src/doc/SkDocument.cpp

+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkDocument.h"
+#include "SkStream.h"
+
+SkDocument::SkDocument(SkWStream* stream, void (*doneProc)(SkWStream*)) {
+    fStream = stream;   // we do not own this object.
+    fDoneProc = doneProc;
+    fState = kBetweenPages_State;
+}
+
+SkDocument::~SkDocument() {
+    this->close();
+}
+
+SkCanvas* SkDocument::beginPage(SkScalar width, SkScalar height,
+                                const SkRect* content) {
+    if (width <= 0 || height <= 0) {
+        return NULL;
+    }
+
+    SkRect outer = SkRect::MakeWH(width, height);
+    SkRect inner;
+    if (content) {
+        inner = *content;
+        if (!inner.intersect(outer)) {
+            return NULL;
+        }
+    } else {
+        inner = outer;
+    }
+
+    for (;;) {
+        switch (fState) {
+            case kBetweenPages_State:
+                fState = kInPage_State;
+                return this->onBeginPage(width, height, inner);
+            case kInPage_State:
+                this->endPage();
+                break;
+            case kClosed_State:
+                return NULL;
+        }
+    }
+    SkASSERT(!"never get here");
+    return NULL;
+}
+
+void SkDocument::endPage() {

[wrong vandebo, 2013/06/10 16:41:12]

It seems like this method isn't strictly needed and the method could be
generated implicitly.  I don't object to the method, just noting that it doesn't
seem necessary.

+    if (kInPage_State == fState) {
+        fState = kBetweenPages_State;
+        this->onEndPage();
+    }
+}
+
+void SkDocument::close() {
+    for (;;) {
+        switch (fState) {
+            case kBetweenPages_State:
+                fState = kClosed_State;
+                this->onClose(fStream);
+
+                if (fDoneProc) {
+                    fDoneProc(fStream);
+                }
+                // we don't own the stream, but we mark it NULL since we can
+                // no longer write to it.
+                fStream = NULL;
+                return;
+            case kInPage_State:
+                this->endPage();
+                break;
+            case kClosed_State:
+                return;
+        }
+    }
+}
+