add patch and clicktracking to lua

resources/slides2.lua

Index: resources/slides2.lua
diff --git a/resources/slides.lua b/resources/slides2.lua
similarity index 73%
copy from resources/slides.lua
copy to resources/slides2.lua
index 43c9b3b32fa307d8f00d5146ed34335965c4a35f..a74a8d5bc6c6972fc786605937d64ef31ba0cdbd 100644
--- a/resources/slides.lua
+++ b/resources/slides2.lua
@@ -290,42 +290,161 @@ function spawn_scale_animation()
     }
 end
 
-local bgPaint = nil
-
-function draw_bg(canvas)
-    if not bgPaint then
-        bgPaint = Sk.newPaint()
-        local grad = Sk.newLinearGradient(  0,   0, { a=1, r=0, g=0, b=.3 },
-                                          640, 480, { a=1, r=0, g=0, b=.8 })
-        bgPaint:setShader(grad)
-        bgPaint:setDither(true)
-    end
+local bgPaint = Sk.newPaint()
 
+function draw_bg(canvas, w, h)
+    bgPaint:setShader(Sk.newLinearGradient(0, 0, { a=1, r=0, g=0, b=.3 },
+                                           w, h, { a=1, r=0, g=0, b=.8 }))
     canvas:drawPaint(bgPaint)
 end
 
-function onDrawContent(canvas, width, height)
-    local matrix = Sk.newMatrix()
-    matrix:setRectToRect(make_rect(0, 0, 640, 480), make_rect(0, 0, width, height), "center")
-    canvas:concat(matrix)
+function draw_drag(canvas)
+    local paint = Sk.newPaint()
+    if gDragPts then
+        local r = make_rect(gDragPts[1], gDragPts[2], gDragPts[3], gDragPts[4])
+        canvas:drawRect(r, paint)
+    end
+end
+
+function setpt(array, index, x, y)
+    local i = index * 2 - 1
+    array[i + 0] = x
+    array[i + 1] = y
+end
+
+function make_patch_cubics(minX, minY, maxX, maxY)
+    local dx = (maxX - minX) / 3
+    local dy = (maxY - minY) / 3
+
+    cubics = {}

[robertphillips, 2014/11/07 18:02:54]

// bottom

+    for i = 0, 2 do
+        setpt(cubics, 1 + i, minX + dx * i, minY)
+    end

[robertphillips, 2014/11/07 18:02:54]

// right 

+    for i = 0, 2 do
+        setpt(cubics, 4 + i, maxX, minY + dy * i)
+    end

[robertphillips, 2014/11/07 18:02:54]

// top

+    for i = 0, 2 do
+        setpt(cubics, 7 + i, maxX - dx * i, maxY)
+    end

[robertphillips, 2014/11/07 18:02:54]

// left

+    for i = 0, 2 do
+        setpt(cubics, 10 + i, minX, maxY - dy * i)
+    end
+
+    return cubics
+end
+
+gCubics = make_patch_cubics(10, 10, 630, 470)
+

[robertphillips, 2014/11/07 18:02:54]

There doesn't seem to be any way to change this guy.

+gPatchDelta = { x = 0, y = 0 }
+

[robertphillips, 2014/11/07 18:02:54]

distSq instead ?

+function dist(x, y, x1, y1)
+    local dx = x - x1
+    local dy = y - y1
+    return math.sqrt(dx * dx + dy * dy)
+end
+
+function find_cubics_index(x, y)
+    x = x - gPatchDelta.x
+    y = y - gPatchDelta.y
+    for i = 1, 12 do
+        local index = i * 2 - 1
+        local cx = gCubics[index + 0]
+        local cy = gCubics[index + 1]
+        if dist(x, y, cx, cy) <= 5 then
+            return index
+        end
+    end
+    return nil
+end
+
+function set_cubic_pt(index, x, y)
+    gCubics[index + 0] = x - gPatchDelta.x
+    gCubics[index + 1] = y - gPatchDelta.y
+end
+
+function draw_ctrl(canvas, x, y, paint)
+    local n = 4
+    canvas:drawRect(make_rect(x - n, y - n, x + n, y + n), paint)
+end
+
+gBlackPaint = Sk.newPaint()
 
-    draw_bg(canvas)
+function show_patch(canvas, paint, width, height)
+    local colors = nil
+    local texs = nil
 
+    if width and height then
+        texs = { 0, 0,      width, 0,       width, height,      0, height }
+    end
+
+    canvas:save()
+    canvas:translate(gPatchDelta.x, gPatchDelta.y)
+    canvas:drawPatch(gCubics, colors, texs, paint)
+
+    for i = 1, 12 do
+        local index = i * 2 - 1
+        local x = gCubics[index + 0]
+        local y = gCubics[index + 1]
+        draw_ctrl(canvas, x, y, gBlackPaint)
+    end
+
+    canvas:restore()
+end
+
+gCTM = Sk.newMatrix()
+
+function drawSlideIntoCanvas(canvas)
     local drawSlideProc = function(canvas)
         drawSlide(canvas, gSlides[gSlideIndex], gTemplate)
     end
 
     if gCurrAnimation then
         gCurrAnimation = gCurrAnimation:proc(canvas, drawSlideProc)
-        return true
     else
         drawSlideProc(canvas)
-        return false
     end
 end
 
-function onClickHandler(x, y)
-    return false
+function onDrawContent(canvas, width, height)

[robertphillips, 2014/11/07 18:02:54]

add some comments here ?

// We render the slide contents to a 640x480 image and
// then apply that (as a shader) to a patch to effect 
// the final (warped) rendering

?

+    gCTM:setRectToRect(make_rect(0, 0, 640, 480), make_rect(0, 0, width, height), "center")
+
+    draw_bg(canvas, width, height)
+
+    local surf = canvas:newSurface(640, 480)
+    drawSlideIntoCanvas(surf:getCanvas())
+
+    canvas:concat(gCTM)
+
+    local image = surf:newImageSnapshot()
+    local paint = Sk.newPaint()
+    paint:setShader(image:newShader())
+    paint:setFilterLevel(1)

[robertphillips, 2014/11/07 18:02:54]

I'm a bit surprised we don't have an option to not draw through a patch.

+    show_patch(canvas, paint, image:width(), image:height())
+
+    return not (not gCurrAnimation)
+end
+

[robertphillips, 2014/11/07 18:02:54]

This and draw_drag don't appear to be used.

+gDragPts = nil
+
+gDragCubicIndex = nil
+
+function onClickHandler(x, y, state)
+    local inv = Sk.newMatrix()
+    gCTM:invert(inv)
+    x, y = inv:mapXY(x, y)
+
+    if state == "down" then
+        gDragCubicIndex = find_cubics_index(x, y)
+        if gDragCubicIndex == nil then
+            return false
+        end
+    end
+
+    if gDragCubicIndex and (state == "moved") then
+        set_cubic_pt(gDragCubicIndex, x, y)
+    end
+
+    return true
 end
 
 local keyProcs = {