add key handlers to lua

BUG=skia:
TBR=

Review URL: https://codereview.chromium.org/652473002

resources/slides.lua

@@ -2,6 +2,7 @@
 function make_paint(size, color)
     local paint = Sk.newPaint();
     paint:setAntiAlias(true)
+    paint:setSubpixelText(true)
     paint:setTextSize(size)
     paint:setColor(color)
     return paint
@@ -81,28 +82,107 @@ gSlides = {
     }
 }
 
-gSlideIndex = 1
-
 --------------------------------------------------------------------------------------
 
-function onDrawContent(canvas)
-    drawSlide(canvas, gSlides[gSlideIndex], gTemplate, gPaints)
+gSlideIndex = 1
 
-    return false -- we're not animating
-end
-
-function onClickHandler(x, y)
-    if x < 100 and y < 100 then
-        onNextSlide()
-        return true
-    end
-    return false
-end
-
-function onNextSlide()
+function next_slide()
     gSlideIndex = gSlideIndex + 1
     if gSlideIndex > #gSlides then
         gSlideIndex = 1
     end
 end
 
+function prev_slide()
+    gSlideIndex = gSlideIndex - 1
+    if gSlideIndex < 1 then
+        gSlideIndex = #gSlides
+    end
+end
+
+--------------------------------------------------------------------------------------
+
+-- animation.proc is passed the canvas before drawing.
+-- The animation.proc returns itself or another animation (which means keep animating)
+-- or it returns nil, which stops the animation.
+--
+local gCurrAnimation
+
+function spawn_rotate_animation()
+    gCurrAnimation = {
+        angle = 0,
+        angle_delta = 5,
+        pivot_x = 320,
+        pivot_y = 240,
+        proc = function (this, canvas)
+            if this.angle >= 360 then
+                return nil
+            end
+            canvas:translate(this.pivot_x, this.pivot_y)
+            canvas:rotate(this.angle)
+            canvas:translate(-this.pivot_x, -this.pivot_y)
+
+            this.angle = this.angle + this.angle_delta
+            return this
+        end
+    }
+end
+
+function spawn_scale_animation()
+    gCurrAnimation = {
+        scale = 1,
+        scale_delta = .95,
+        scale_limit = 0.2,
+        pivot_x = 320,
+        pivot_y = 240,
+        proc = function (this, canvas)
+            if this.scale < this.scale_limit then
+                this.scale = this.scale_limit
+                this.scale_delta = 1 / this.scale_delta
+            end
+            if this.scale > 1 then
+                return nil
+            end
+            canvas:translate(this.pivot_x, this.pivot_y)
+            canvas:scale(this.scale, this.scale)
+            canvas:translate(-this.pivot_x, -this.pivot_y)
+
+            this.scale = this.scale * this.scale_delta
+            return this
+        end
+    }
+end
+
+function onDrawContent(canvas)
+    if gCurrAnimation then
+        gCurrAnimation = gCurrAnimation:proc(canvas)
+    end
+
+    drawSlide(canvas, gSlides[gSlideIndex], gTemplate, gPaints)
+
+    if gCurrAnimation then
+        return true
+    else
+        return false
+    end
+end
+
+function onClickHandler(x, y)
+    return false
+end
+
+local keyProcs = {
+    n = next_slide,
+    p = prev_slide,
+    r = spawn_rotate_animation,
+    s = spawn_scale_animation,
+}
+
+function onCharHandler(uni)
+    local proc = keyProcs[uni]
+    if proc then
+        proc()
+        return true
+    end
+    return false
+end

samplecode/SampleLua.cpp

@@ -23,6 +23,7 @@ extern "C" {
 
 static const char gDrawName[] = "onDrawContent";
 static const char gClickName[] = "onClickHandler";
+static const char gUnicharName[] = "onCharHandler";
 
 static const char gMissingCode[] = ""
     "local paint = Sk.newPaint()"
@@ -79,6 +80,21 @@ protected:
         }
         SkUnichar uni;
         if (SampleCode::CharQ(*evt, &uni)) {
+            lua_State* L = this->ensureLua();
+            lua_getglobal(L, gUnicharName);
+            if (lua_isfunction(L, -1)) {
+                SkString str;
+                str.appendUnichar(uni);
+                fLua->pushString(str.c_str());
+                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);
+                        return true;
+                    }
+                }
+            }
         }
         return this->INHERITED::onQuery(evt);
     }

src/utils/SkLua.cpp

@@ -693,6 +693,11 @@ static int lpaint_isSubpixelText(lua_State* L) {
     return 1;
 }
 
+static int lpaint_setSubpixelText(lua_State* L) {
+    get_obj<SkPaint>(L, 1)->setSubpixelText(lua2bool(L, 2));
+    return 1;
+}
+
 static int lpaint_isDevKernText(lua_State* L) {
     lua_pushboolean(L, get_obj<SkPaint>(L, 1)->isDevKernText());
     return 1;
@@ -936,6 +941,7 @@ static const struct luaL_Reg gSkPaint_Methods[] = {
     { "isFakeBoldText", lpaint_isFakeBoldText },
     { "isLinearText", lpaint_isLinearText },
     { "isSubpixelText", lpaint_isSubpixelText },
+    { "setSubpixelText", lpaint_setSubpixelText },
     { "isDevKernText", lpaint_isDevKernText },
     { "isLCDRenderText", lpaint_isLCDRenderText },
     { "isEmbeddedBitmapText", lpaint_isEmbeddedBitmapText },