added clip visualization to skiaserve

GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1690023004

Review URL: https://codereview.chromium.org/1690023004

tools/debugger/SkDebugCanvas.cpp

@@ -67,7 +67,8 @@ SkDebugCanvas::SkDebugCanvas(int width, int height)
         , fMegaVizMode(false)
         , fOverdrawViz(false)
         , fOverrideFilterQuality(false)
-        , fFilterQuality(kNone_SkFilterQuality) {
+        , fFilterQuality(kNone_SkFilterQuality)
+        , fClipVizColor(SK_ColorTRANSPARENT) {
     fUserMatrix.reset();
 
     // SkPicturePlayback uses the base-class' quickReject calls to cull clipped
@@ -233,6 +234,17 @@ void SkDebugCanvas::drawTo(SkCanvas* canvas, int index) {
         }
     }
 
+    if (SkColorGetA(fClipVizColor) != 0) {
+        canvas->save();
+        #define LARGE_COORD 1000000000
+        canvas->clipRect(SkRect::MakeLTRB(-LARGE_COORD, -LARGE_COORD, LARGE_COORD, LARGE_COORD),
+                       SkRegion::kReverseDifference_Op);
+        SkPaint clipPaint;
+        clipPaint.setColor(fClipVizColor);
+        canvas->drawPaint(clipPaint);
+        canvas->restore();
+    }
+
     if (fMegaVizMode) {
         canvas->save();
         // nuke the CTM
@@ -323,7 +335,7 @@ Json::Value SkDebugCanvas::toJSON(UrlDataManager& urlDataManager, int n) {
     Json::Value result = Json::Value(Json::objectValue);
     result[SKDEBUGCANVAS_ATTRIBUTE_VERSION] = Json::Value(SKDEBUGCANVAS_VERSION);
     Json::Value commands = Json::Value(Json::arrayValue);
-    for (int i = 0; i < this->getSize() && i < n; i++) {
+    for (int i = 0; i < this->getSize() && i <= n; i++) {
         commands[i] = this->getDrawCommandAt(i)->toJSON(urlDataManager);
     }
     result[SKDEBUGCANVAS_ATTRIBUTE_COMMANDS] = commands;

tools/debugger/SkDebugCanvas.h

@@ -37,6 +37,12 @@ public:
     void setOverdrawViz(bool overdrawViz);
     bool getOverdrawViz() const { return fOverdrawViz; }
 
+    /**
+     * Set the color of the clip visualization. An alpha of zero renders the clip invisible.
+     */
+    void setClipVizColor(SkColor clipVizColor) { this->fClipVizColor = clipVizColor; }
+    SkColor getClipVizColor() const { return fClipVizColor; }
+
     bool getAllowSimplifyClip() const { return fAllowSimplifyClip; }
 
     void setPicture(SkPicture* picture) { fPicture = picture; }
@@ -141,9 +147,9 @@ public:
     SkString clipStackData() const { return fClipStackData; }
 
     /**
-        Returns a JSON object representing up to N draws, where N is <= SkDebugCanvas::getSize().
-        The encoder may use the UrlDataManager to store binary data such as images, referring to
-        them via URLs embedded in the JSON.
+        Returns a JSON object representing up to the Nth draw, where N is less than
+        SkDebugCanvas::getSize(). The encoder may use the UrlDataManager to store binary data such 
+        as images, referring to them via URLs embedded in the JSON.
      */
     Json::Value toJSON(UrlDataManager& urlDataManager, int n);
 
@@ -238,6 +244,7 @@ private:
     bool fOverdrawViz;
     bool fOverrideFilterQuality;
     SkFilterQuality fFilterQuality;
+    SkColor fClipVizColor;
 
     SkAutoTUnref<SkNWayCanvas> fPaintFilterCanvas;
 

tools/skiaserve/skiaserve.cpp

@@ -232,7 +232,7 @@ public:
         if (0 == strcmp(method, MHD_HTTP_METHOD_GET)) {
             int n;
             if (commands.count() == 1) {
-                n = request->fDebugCanvas->getSize();
+                n = request->fDebugCanvas->getSize() - 1;
             } else {
                 sscanf(commands[1].c_str(), "%d", &n);
             }
@@ -291,6 +291,36 @@ public:
     }
 };
 
+/**
+   Updates the clip visualization alpha. On all subsequent /img requests, the clip will be drawn in
+   black with the specified alpha. 0 = no visible clip, 255 = fully opaque clip.
+ */
+class ClipAlphaHandler : public UrlHandler {
+public:
+    bool canHandle(const char* method, const char* url) override {
+        static const char* kBasePath = "/clipAlpha/";
+        return 0 == strcmp(method, MHD_HTTP_METHOD_GET) &&
+               0 == strncmp(url, kBasePath, strlen(kBasePath));
+    }
+
+    int handle(Request* request, MHD_Connection* connection,
+               const char* url, const char* method,
+               const char* upload_data, size_t* upload_data_size) override {
+        SkTArray<SkString> commands;
+        SkStrSplit(url, "/", &commands);
+
+        if (!request->fPicture.get() || commands.count() != 2) {
+            return MHD_NO;
+        }
+
+        int alpha;
+        sscanf(commands[1].c_str(), "%d", &alpha);
+
+        request->fDebugCanvas->setClipVizColor(SkColorSetARGB(alpha, 0, 0, 0));
+        return SendOK(connection);
+    }
+};
+
 class PostHandler : public UrlHandler {
 public:
     bool canHandle(const char* method, const char* url) override {
@@ -508,6 +538,7 @@ public:
         fHandlers.push_back(new RootHandler);
         fHandlers.push_back(new PostHandler);
         fHandlers.push_back(new ImgHandler);
+        fHandlers.push_back(new ClipAlphaHandler);
         fHandlers.push_back(new CmdHandler);
         fHandlers.push_back(new InfoHandler);
         fHandlers.push_back(new DownloadHandler);