samplecode/SampleLua.cpp

   1 /*
   2  * Copyright 2013 Google Inc.
   3  *
   4  * Use of this source code is governed by a BSD-style license that can be
   5  * found in the LICENSE file.
   6  */
   7
   8 #include "SampleCode.h"
   9 #include "SkView.h"
  10 #include "SkLua.h"
  11 #include "SkCanvas.h"
  12 #include "Resources.h"
  13 #include "SkData.h"
  14
  15 extern "C" {
  16 #include "lua.h"
  17 #include "lualib.h"
  18 #include "lauxlib.h"
  19 }
  20
  21 //#define LUA_FILENAME    "test.lua"
  22 #define LUA_FILENAME    "slides.lua"
  23
  24 static const char gDrawName[] = "onDrawContent";
  25 static const char gClickName[] = "onClickHandler";
  26 static const char gUnicharName[] = "onCharHandler";
  27
  28 static const char gLuaClickHandlerName[] = "lua-click-handler";
  29
  30 static const char gMissingCode[] = ""
  31     "local paint = Sk.newPaint()"
  32     "paint:setAntiAlias(true)"
  33     "paint:setTextSize(30)"
  34     ""
  35     "function onDrawContent(canvas)"
  36     "   canvas:drawText('missing \"test.lua\"', 20, 50, paint)"
  37     "end"
  38     ;
  39
  40 class LuaView : public SampleView {
  41 public:
  42     LuaView() : fLua(NULL) {}
  43
  44     virtual ~LuaView() {
  45         SkDELETE(fLua);
  46     }
  47
  48     void setImageFilename(lua_State* L) {
  49         SkString str = GetResourcePath("mandrill_256.png");
  50
  51         lua_getglobal(L, "setImageFilename");
  52         if (lua_isfunction(L, -1)) {
  53             fLua->pushString(str.c_str());
  54             if (lua_pcall(L, 1, 0, 0) != LUA_OK) {
  55                 SkDebugf("lua err: %s\n", lua_tostring(L, -1));
  56             }
  57         }
  58     }
  59
  60     lua_State* ensureLua() {
  61         if (NULL == fLua) {
  62             fLua = SkNEW(SkLua);
  63
  64             SkString str = GetResourcePath(LUA_FILENAME);
  65             SkData* data = SkData::NewFromFileName(str.c_str());
  66             if (data) {
  67                 fLua->runCode(data->data(), data->size());
  68                 data->unref();
  69                 this->setImageFilename(fLua->get());
  70             } else {
  71                 fLua->runCode(gMissingCode);
  72             }
  73         }
  74         return fLua->get();
  75     }
  76
  77 protected:
  78     bool onQuery(SkEvent* evt) SK_OVERRIDE {
  79         if (SampleCode::TitleQ(*evt)) {
  80             SampleCode::TitleR(evt, "Lua");
  81             return true;
  82         }
  83         SkUnichar uni;
  84         if (SampleCode::CharQ(*evt, &uni)) {
  85             lua_State* L = this->ensureLua();
  86             lua_getglobal(L, gUnicharName);
  87             if (lua_isfunction(L, -1)) {
  88                 SkString str;
  89                 str.appendUnichar(uni);
  90                 fLua->pushString(str.c_str());
  91                 if (lua_pcall(L, 1, 1, 0) != LUA_OK) {
  92                     SkDebugf("lua err: %s\n", lua_tostring(L, -1));
  93                 } else {
  94                     if (lua_isboolean(L, -1) && lua_toboolean(L, -1)) {
  95                         this->inval(NULL);
  96                         return true;
  97                     }
  98                 }
  99             }
 100         }
 101         return this->INHERITED::onQuery(evt);
 102     }
 103
 104     void onDrawContent(SkCanvas* canvas) SK_OVERRIDE {
 105         lua_State* L = this->ensureLua();
 106
 107         lua_getglobal(L, gDrawName);
 108         if (!lua_isfunction(L, -1)) {
 109             int t = lua_type(L, -1);
 110             SkDebugf("--- expected %s function %d, ignoring.\n", gDrawName, t);
 111             lua_pop(L, 1);
 112         } else {
 113             // does it make sense to try to "cache" the lua version of this
 114             // canvas between draws?
 115             fLua->pushCanvas(canvas);
 116             fLua->pushScalar(this->width());
 117             fLua->pushScalar(this->height());
 118             if (lua_pcall(L, 3, 1, 0) != LUA_OK) {
 119                 SkDebugf("lua err: %s\n", lua_tostring(L, -1));
 120             } else {
 121                 if (lua_isboolean(L, -1) && lua_toboolean(L, -1)) {
 122                     this->inval(NULL);
 123                 }
 124             }
 125         }
 126     }
 127
 128     virtual SkView::Click* onFindClickHandler(SkScalar x, SkScalar y,
 129                                               unsigned modi) SK_OVERRIDE {
 130         lua_State* L = this->ensureLua();
 131         lua_getglobal(L, gClickName);
 132         if (lua_isfunction(L, -1)) {
 133             fLua->pushScalar(x);
 134             fLua->pushScalar(y);
 135             fLua->pushString("down");
 136             if (lua_pcall(L, 3, 1, 0) != LUA_OK) {
 137                 SkDebugf("lua err: %s\n", lua_tostring(L, -1));
 138             } else {
 139                 if (lua_isboolean(L, -1) && lua_toboolean(L, -1)) {
 140                     this->inval(NULL);
 141                     Click* c = new Click(this);
 142                     c->setType(gLuaClickHandlerName);
 143                     return c;
 144                 }
 145             }
 146         }
 147         return this->INHERITED::onFindClickHandler(x, y, modi);
 148     }
 149
 150     bool onClick(Click* click) SK_OVERRIDE {
 151         if (click->getType() != gLuaClickHandlerName) {
 152             return this->INHERITED::onClick(click);
 153         }
 154
 155         const char* state = NULL;
 156         switch (click->fState) {
 157             case Click::kMoved_State:
 158                 state = "moved";
 159                 break;
 160             case Click::kUp_State:
 161                 state = "up";
 162                 break;
 163             default:
 164                 break;
 165         }
 166         if (state) {
 167             this->inval(NULL);
 168             lua_State* L = fLua->get();
 169             lua_getglobal(L, gClickName);
 170             fLua->pushScalar(click->fCurr.x());
 171             fLua->pushScalar(click->fCurr.y());
 172             fLua->pushString(state);
 173             lua_pcall(L, 3, 1, 0);
 174             return lua_isboolean(L, -1) && lua_toboolean(L, -1);
 175         }
 176         return true;
 177     }
 178
 179 private:
 180     SkLua* fLua;
 181
 182     typedef SampleView INHERITED;
 183 };
 184
 185 //////////////////////////////////////////////////////////////////////////////
 186
 187 static SkView* MyFactory() { return new LuaView; }
 188 static SkViewRegister reg(MyFactory);