allow for lua click handlers

BUG=skia:
TBR=

Review URL: https://codereview.chromium.org/649013002

resources/slides.lua

@@ -0,0 +1,108 @@
+
+function make_paint(size, color)
+    local paint = Sk.newPaint();
+    paint:setAntiAlias(true)
+    paint:setTextSize(size)
+    paint:setColor(color)
+    return paint
+end
+
+function find_paint(paints, style)
+    if not style then
+        style = "child"
+    end
+    local paint = paints[style]
+    return paint
+end
+
+function draw_node(canvas, node, x, y, paints)
+    if node.text then
+        local paint = find_paint(paints, node.style)
+        canvas:drawText(node.text, x, y, paint)
+    end
+    if node.draw then
+        node.draw(canvas)
+    end
+end
+
+function drawSlide(canvas, slide, template, paints)
+    draw_node(canvas, slide, template.title.x, template.title.y, paints)
+
+    if slide.children then
+        local x = template.child.x
+        local y = template.child.y
+        local dy = template.child.dy
+        for i = 1, #slide.children do
+            draw_node(canvas, slide.children[i], x, y, paints)
+            y = y + dy
+        end
+    end
+end
+
+--------------------------------------------------------------------------------------
+
+gTemplate = {
+    title = { x = 10, y = 64, textSize = 64 },
+    child = { x = 40, y = 120, dy = 50, textSize = 40 },
+}
+
+gPaints = {}
+gPaints.title = make_paint(gTemplate.title.textSize, { a=1, r=0, g=0, b=0 } )
+gPaints.child = make_paint(gTemplate.child.textSize, { a=.75, r=0, g=0, b=0 } )
+
+gRedPaint = Sk.newPaint()
+gRedPaint:setAntiAlias(true)
+gRedPaint:setColor{a=1, r=1, g=0, b=0 }
+
+gSlides = {
+    {   text = "Title1", style="title", color = { a=1, r=1, g=0, b=0 },
+        children = {
+            {   text = "bullet 1", style = "child" },
+            {   text = "bullet 2", style = "child" },
+            {   text = "bullet 3", style = "child" },
+            {   draw = function (canvas)
+                    canvas:drawOval({left=300, top=300, right=400, bottom=400}, gRedPaint)
+            end },
+        },
+    },
+    {   text = "Title2", style="title", color = { a=1, r=0, g=1, b=0 },
+        children = {
+            {   text = "bullet uno", style = "child" },
+            {   text = "bullet 2", style = "child" },
+            {   text = "bullet tres", style = "child" },
+        }
+    },
+    {   text = "Title3", style="title",
+        children = {
+            {   text = "bullet 1", style = "child", },
+            {   text = "bullet 2", style = "child", color = { r=0, g=0, b=1 } },
+            {   text = "bullet 3", style = "child" },
+        }
+    }
+}
+
+gSlideIndex = 1
+
+--------------------------------------------------------------------------------------
+
+function onDrawContent(canvas)
+    drawSlide(canvas, gSlides[gSlideIndex], gTemplate, gPaints)
+
+    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()
+    gSlideIndex = gSlideIndex + 1
+    if gSlideIndex > #gSlides then
+        gSlideIndex = 1
+    end
+end
+

resources/test.lua

@@ -69,6 +69,8 @@ function onDrawContent(canvas)
     r2.bottom = r2.top + image:height() * 1;
     canvas:drawImageRect(image, nil, r2, 0.75);
     if x > 200 then x = 0 end;
+
+    return true -- so we can animate
 end
 
 onStartup()

samplecode/SampleLua.cpp

@@ -18,7 +18,11 @@ extern "C" {
 #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()"
@@ -54,7 +58,7 @@ public:
         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());
@@ -91,17 +95,31 @@ protected:
             // 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);
     }