allow for lua click handlers

samplecode/SampleLua.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 "SampleCode.h"
 #include "SkView.h"
 #include "SkLua.h"
 #include "SkCanvas.h"
 #include "Resources.h"
 #include "SkData.h"
 
 extern "C" {
 #include "lua.h"
 #include "lualib.h"
 #include "lauxlib.h"
 }
 
+#define LUA_FILENAME    "test.lua"
+//#define LUA_FILENAME    "slides.lua"
+
 static const char gDrawName[] = "onDrawContent";
+static const char gClickName[] = "onClickHandler";
 
 static const char gMissingCode[] = ""
     "local paint = Sk.newPaint()"
     "paint:setAntiAlias(true)"
     "paint:setTextSize(30)"
     ""
     "function onDrawContent(canvas)"
     "   canvas:drawText('missing \"test.lua\"', 20, 50, paint)"
     "end"
     ;
@@ skipping 15 matching lines @@
             if (lua_pcall(L, 1, 0, 0) != LUA_OK) {
                 SkDebugf("lua err: %s\n", lua_tostring(L, -1));
             }
         }
     }
 
     lua_State* ensureLua() {
         if (NULL == fLua) {
             fLua = SkNEW(SkLua);
 
-            SkString str = GetResourcePath("test.lua");
+            SkString str = GetResourcePath(LUA_FILENAME);
             SkData* data = SkData::NewFromFileName(str.c_str());
             if (data) {
                 fLua->runCode(data->data(), data->size());
                 data->unref();
                 this->setImageFilename(fLua->get());
             } else {
                 fLua->runCode(gMissingCode);
             }
         }
         return fLua->get();
@@ skipping 16 matching lines @@
 
         lua_getglobal(L, gDrawName);
         if (!lua_isfunction(L, -1)) {
             int t = lua_type(L, -1);
             SkDebugf("--- expected %s function %d, ignoring.\n", gDrawName, t);
             lua_pop(L, 1);
         } else {
             // does it make sense to try to "cache" the lua version of this
             // canvas between draws?
             fLua->pushCanvas(canvas);
-            if (lua_pcall(L, 1, 0, 0) != LUA_OK) {
+            if (lua_pcall(L, 1, 1, 0) != LUA_OK) {
                 SkDebugf("lua err: %s\n", lua_tostring(L, -1));
+            } else {
+                if (lua_isboolean(L, -1) && lua_toboolean(L, -1)) {
+                    this->inval(NULL);
+                }
             }
         }
-        // need a way for the lua-sample to tell us if they want animations...
-        // hard-code it ON for now.
-        this->inval(NULL);
     }
 
     virtual SkView::Click* onFindClickHandler(SkScalar x, SkScalar y,
                                               unsigned modi) SK_OVERRIDE {
+        lua_State* L = this->ensureLua();
+        lua_getglobal(L, gClickName);
+        if (lua_isfunction(L, -1)) {
+            fLua->pushScalar(x);
+            fLua->pushScalar(y);
+            if (lua_pcall(L, 2, 1, 0) != LUA_OK) {
+                SkDebugf("lua err: %s\n", lua_tostring(L, -1));
+            } else {
+                if (lua_isboolean(L, -1) && lua_toboolean(L, -1)) {
+                    this->inval(NULL);
+                }
+            }
+        }
         return this->INHERITED::onFindClickHandler(x, y, modi);
     }
 
     virtual bool onClick(Click* click) SK_OVERRIDE {
         return this->INHERITED::onClick(click);
     }
 
 private:
     SkLua* fLua;
 
     typedef SampleView INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static SkView* MyFactory() { return new LuaView; }
 static SkViewRegister reg(MyFactory);