diff options
author | 2013-12-06 15:24:52 +0000 | |
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committer | 2013-12-06 15:24:52 +0000 | |
commit | 80bd0c995d9ec6a70330d6dc3f2f8dd387701d1d (patch) | |
tree | d75dee2dc13abead1324ddeb2661ffa819b7b61e /experimental/SkV8Example | |
parent | 650660212dcffc1fe75129d4275755172a91b0a2 (diff) |
A simple draw() function in Javascript.
R=robertphillips@google.com
Author: jcgregorio@google.com
Review URL: https://codereview.chromium.org/102803003
git-svn-id: http://skia.googlecode.com/svn/trunk@12527 2bbb7eff-a529-9590-31e7-b0007b416f81
Diffstat (limited to 'experimental/SkV8Example')
-rw-r--r-- | experimental/SkV8Example/SkV8Example.cpp | 171 | ||||
-rw-r--r-- | experimental/SkV8Example/SkV8Example.h | 16 |
2 files changed, 163 insertions, 24 deletions
diff --git a/experimental/SkV8Example/SkV8Example.cpp b/experimental/SkV8Example/SkV8Example.cpp index 4cb16bebe9..93f9d707cc 100644 --- a/experimental/SkV8Example/SkV8Example.cpp +++ b/experimental/SkV8Example/SkV8Example.cpp @@ -31,19 +31,78 @@ void application_term() { SkGraphics::Term(); } -SkV8ExampleWindow::SkV8ExampleWindow(void* hwnd) - : INHERITED(hwnd) { +// Extracts a C string from a V8 Utf8Value. +const char* ToCString(const v8::String::Utf8Value& value) { + return *value ? *value : "<string conversion failed>"; +} + +// Slight modification to an original function found in the V8 sample shell.cc. +void reportException(Isolate* isolate, TryCatch* try_catch) { + HandleScope handle_scope(isolate); + String::Utf8Value exception(try_catch->Exception()); + const char* exception_string = ToCString(exception); + Handle<Message> message = try_catch->Message(); + if (message.IsEmpty()) { + // V8 didn't provide any extra information about this error; just + // print the exception. + fprintf(stderr, "%s\n", exception_string); + } else { + // Print (filename):(line number): (message). + String::Utf8Value filename(message->GetScriptResourceName()); + const char* filename_string = ToCString(filename); + int linenum = message->GetLineNumber(); + fprintf(stderr, "%s:%i: %s\n", filename_string, linenum, exception_string); + // Print line of source code. + String::Utf8Value sourceline(message->GetSourceLine()); + const char* sourceline_string = ToCString(sourceline); + fprintf(stderr, "%s\n", sourceline_string); + // Print wavy underline. + int start = message->GetStartColumn(); + for (int i = 0; i < start; i++) { + fprintf(stderr, " "); + } + int end = message->GetEndColumn(); + for (int i = start; i < end; i++) { + fprintf(stderr, "^"); + } + fprintf(stderr, "\n"); + String::Utf8Value stack_trace(try_catch->StackTrace()); + if (stack_trace.length() > 0) { + const char* stack_trace_string = ToCString(stack_trace); + fprintf(stderr, "%s\n", stack_trace_string); + } + } +} +SkV8ExampleWindow::SkV8ExampleWindow(void* hwnd, + Isolate* isolate, + Handle<Context> context, + Handle<Script> script) + : INHERITED(hwnd) + , fIsolate(isolate) +{ + // Convert the Handle<> objects into Persistent<> objects using Reset(). + fContext.Reset(isolate, context); + fScript.Reset(isolate, script); + + fRotationAngle = SkIntToScalar(0); this->setConfig(SkBitmap::kARGB_8888_Config); this->setVisibleP(true); this->setClipToBounds(false); } +// Simple global for the Draw function. +SkCanvas* gCanvas = NULL; -void SkV8ExampleWindow::onDraw(SkCanvas* canvas) { - printf("Draw\n"); - canvas->drawColor(SK_ColorWHITE); +// Draw is called from within V8 when the Javascript function draw() is called. +void Draw(const v8::FunctionCallbackInfo<v8::Value>& args) { + if (NULL == gCanvas) { + printf("Can't Draw Now.\n"); + return; + } + + gCanvas->drawColor(SK_ColorWHITE); SkPaint paint; paint.setColor(SK_ColorRED); @@ -52,11 +111,64 @@ void SkV8ExampleWindow::onDraw(SkCanvas* canvas) { SkIntToScalar(10), SkIntToScalar(10), SkIntToScalar(128), SkIntToScalar(128) }; - canvas->drawRect(rect, paint); + gCanvas->drawRect(rect, paint); +} + +void SkV8ExampleWindow::onDraw(SkCanvas* canvas) { + printf("Draw\n"); + + gCanvas = canvas; + canvas->save(); + fRotationAngle += SkDoubleToScalar(0.2); + if (fRotationAngle > SkDoubleToScalar(360.0)) { + fRotationAngle -= SkDoubleToScalar(360.0); + } + canvas->rotate(fRotationAngle); + + // Create a Handle scope for temporary references. + HandleScope handle_scope(fIsolate); + + // Create a local context from our persistent context. + Local<Context> context = + Local<Context>::New(fIsolate, fContext); + + // Enter the context so all operations take place within it. + Context::Scope context_scope(context); + + TryCatch try_catch; + + // Create a local script from our persistent script. + Local<Script> script = + Local<Script>::New(fIsolate, fScript); + + // Run the script. + Handle<Value> result = script->Run(); + + if (result.IsEmpty()) { + SkASSERT(try_catch.HasCaught()); + // Print errors that happened during execution. + reportException(fIsolate, &try_catch); + } else { + SkASSERT(!try_catch.HasCaught()); + if (!result->IsUndefined()) { + // If all went well and the result wasn't undefined then print + // the returned value. + String::Utf8Value str(result); + const char* cstr = ToCString(str); + printf("%s\n", cstr); + } + } + + canvas->restore(); + + // Trigger an invalidation which should trigger another redraw to simulate + // animation. + this->inval(NULL); INHERITED::onDraw(canvas); } + #ifdef SK_BUILD_FOR_WIN void SkV8ExampleWindow::onHandleInval(const SkIRect& rect) { RECT winRect; @@ -68,41 +180,54 @@ void SkV8ExampleWindow::onHandleInval(const SkIRect& rect) { } #endif +// Creates a new execution environment containing the built-in +// function draw(). +Handle<Context> createRootContext(Isolate* isolate) { + // Create a template for the global object. + Handle<ObjectTemplate> global = ObjectTemplate::New(); + // Bind the global 'draw' function to the C++ Draw callback. + global->Set(String::NewFromUtf8(isolate, "draw"), + FunctionTemplate::New(Draw)); + + return Context::New(isolate, NULL, global); +} SkOSWindow* create_sk_window(void* hwnd, int argc, char** argv) { printf("Started\n"); // Get the default Isolate created at startup. Isolate* isolate = Isolate::GetCurrent(); + printf("Isolate\n"); // Create a stack-allocated handle scope. HandleScope handle_scope(isolate); + printf("Before create context\n"); // Create a new context. - Handle<Context> context = Context::New(isolate); + // + Handle<Context> context = createRootContext(isolate); - // Here's how you could create a Persistent handle to the context, if needed. - Persistent<Context> persistent_context(isolate, context); - - // Enter the created context for compiling and - // running the hello world script. + // Enter the scope so all operations take place in the scope. Context::Scope context_scope(context); - // Create a string containing the JavaScript source code. - Handle<String> source = String::New("'Hello' + ', World!'"); + v8::TryCatch try_catch; // Compile the source code. + Handle<String> source = String::NewFromUtf8(isolate, "draw();"); + printf("Before Compile\n"); Handle<Script> script = Script::Compile(source); + printf("After Compile\n"); - // Run the script to get the result. - Handle<Value> result = script->Run(); - - // The persistent handle needs to be eventually disposed. - persistent_context.Dispose(); + // Try running it now. It won't have a valid context, but shouldn't fail. + script->Run(); - // Convert the result to an ASCII string and print it. - String::AsciiValue ascii(result); - printf("%s\n", *ascii); + if (script.IsEmpty()) { + // Print errors that happened during compilation. + reportException(isolate, &try_catch); + exit(1); + } + printf("After Exception.\n"); - return new SkV8ExampleWindow(hwnd); + // SkV8ExampleWindow will make persistent handles to hold the context and script. + return new SkV8ExampleWindow(hwnd, isolate, context, script); } diff --git a/experimental/SkV8Example/SkV8Example.h b/experimental/SkV8Example/SkV8Example.h index dc87b21d68..97cf580171 100644 --- a/experimental/SkV8Example/SkV8Example.h +++ b/experimental/SkV8Example/SkV8Example.h @@ -10,26 +10,40 @@ #ifndef SkV8Example_DEFINED #define SkV8Example_DEFINED +#include <v8.h> + #include "SkWindow.h" + +using namespace v8; + + class SkCanvas; class SkV8ExampleWindow : public SkOSWindow { public: - SkV8ExampleWindow(void* hwnd); + SkV8ExampleWindow(void* hwnd, + Isolate* isolate, + Handle<Context> context, + Handle<Script> script); protected: virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE; + #ifdef SK_BUILD_FOR_WIN virtual void onHandleInval(const SkIRect&) SK_OVERRIDE; #endif private: typedef SkOSWindow INHERITED; + Isolate* fIsolate; + Persistent<Context> fContext; + Persistent<Script> fScript; + SkScalar fRotationAngle; }; #endif |