Move draw method from GradientElement to GradientRendering

src/element.toit

@@ -177,6 +177,9 @@ class GradientRendering_:
   green_pixels_/ByteArray? := null
   blue_pixels_/ByteArray? := null
   draw_vertical_/bool? := null
+  angle_ /int
+  h_ /int := 0
+  w_ /int := 0
 
   static map_ := Map.weak
 
@@ -190,7 +193,11 @@ class GradientRendering_:
 
   constructor w/int? h/int? gradient/Gradient:
     angle := gradient.angle
+    angle_ = angle
     if h != 0 and h != null and w != 0 and w != null:
+      h_ = h
+      w_ = w
+
       // CSS gradient angles are:
       //    0 bottom to top.
       //   90 left to right
@@ -227,93 +234,10 @@ class GradientRendering_:
           green_pixels_[index] = green
           blue_pixels_[index] = blue
 
-  /// Returns a list of quadruples of the form starting-percent ending-percent start-color end-color.
-  static extract_ranges_ specifiers/List -> List:
-    result := []
-    for i := -1; i < specifiers.size; i++:
-      from := i < 0 ? 0 : specifiers[i].percent
-      to := i >= specifiers.size - 1 ? 100 : specifiers[i + 1].percent
-      if to != from:
-        from_color := specifiers[max i 0].color
-        to_color := specifiers[min (i + 1) (specifiers.size - 1)].color
-        result.add [from, to, from_color, to_color]
-    return result
-
-  static get_colors range/List h/int [block] -> none:
-    from_y := range[0] * h / 100
-    to_y := range[1] * h / 100
-    if to_y == from_y: return
-    divisor := to_y - from_y
-    from_color := range[2]
-    // Use 8.16 fixed point arithmetic to avoid floating point.
-    r := from_color & 0xff0000
-    g := (from_color & 0xff00) << 8
-    b := (from_color & 0xff) << 16
-    to_color := range[3]
-    to_r := to_color & 0xff0000
-    to_g := (to_color & 0xff00) << 8
-    to_b := (to_color & 0xff) << 16
-    step_r := (to_r - r) / divisor
-    step_g := (to_g - g) / divisor
-    step_b := (to_b - b) / divisor
-    for y := from_y; y < to_y; y++:
-      block.call y (r >> 16) (g >> 16) (b >> 16)
-      r += step_r
-      g += step_g
-      b += step_b
-
-/**
-GradientElements are similar to CSS linear gradients and SVG gradients.
-They are given a list of $GradientSpecifier, each of which has a color and
-  a percentage, indicating where in the gradient the color should appear.
-  The specifiers should be ordered in increasing order of percentage.
-Angles are as in CSS, with 0 degrees being up and 90 degrees being to the right
-  (this is different from text orientations, which go anti-clockwise).
-See https://cssgradient.io/ for a visual explanation and playground for CSS
-  gradients.
-Example:
-```
-  gradient = GradientElement --w=200 --h=100 --angle=45
-      --specifiers=[
-          GradientSpecifier --color=0xff0000 10,    // Red from 0-10%, red-to-green from 10-50%.
-          GradientSpecifier --color=0x00ff00 50,    // Green-to-blue from 50-90%.
-          GradientSpecifier --color=0x0000ff 90,    // Blue from 90-100%.
-      ]
-  display.add gradient
-```
-*/
-class GradientElement extends ResizableElement:
-  gradient_/Gradient := ?
-  specification_/GradientSpecification_? := null
-  rendering_/GradientRendering_? := null
-
-  constructor --x/int?=null --y/int?=null --w/int?=null --h/int?=null --gradient/Gradient:
-    gradient_ = gradient
-    super --x=x --y=y --w=w --h=h
-    rendering_ = null
-
-  gradient= gradient/Gradient -> none:
-    if gradient != gradient_:
-      invalidate
-      gradient_ = gradient
-      rendering_ = null
-
-  gradient -> Gradient:
-    return gradient_
-
-  w= value/int -> none:
-    super = value
-    rendering_ = null
-
-  h= value/int -> none:
-    super = value
-    rendering_ = null
-
-  draw canvas/Canvas -> none:
-    if not (x and y and w and h): return
-    if not canvas.supports_8_bit: throw "UNSUPPORTED"
-    if not rendering_: rendering_ = GradientRendering_.get w h gradient_
-    angle := gradient_.angle
+  draw canvas/Canvas x/int y/int -> none:
+    angle := angle_
+    w := w_
+    h := h_
     analysis := canvas.bounds_analysis x y w h
     if analysis == Canvas.ALL_OUTSIDE: return
     // Determine whether the draw operations will be automatically cropped for
@@ -328,7 +252,7 @@ class GradientElement extends ResizableElement:
     //  180 top to bottom
     //  270 right to left
 
-    if rendering_.draw_vertical_:
+    if draw_vertical_:
       // The gradient goes broadly vertically, and we draw in vertical strips.
       up/bool := angle < 90
       orientation/int := ORIENTATION_90
@@ -347,13 +271,13 @@ class GradientElement extends ResizableElement:
         stop = w
         i_step = 1
       offset := 0
-      step := ((rendering_.red_pixels_.size - h) << 16) / w  // n.16 fixed point.
+      step := ((red_pixels_.size - h) << 16) / w  // n.16 fixed point.
       for i := start; i != stop; i += i_step:
         o := offset >> 16
         y3 := ?
-        r := rendering_.red_pixels_
-        g := rendering_.green_pixels_
-        b := rendering_.blue_pixels_
+        r := red_pixels_
+        g := green_pixels_
+        b := blue_pixels_
         if auto_crop:
           if orientation == ORIENTATION_90:
             y3 = y2 + o
@@ -388,13 +312,13 @@ class GradientElement extends ResizableElement:
         stop = h
         i_step = 1
       offset := 0
-      step := ((rendering_.red_pixels_.size - w) << 16) / h  // n.16 fixed point.
+      step := ((red_pixels_.size - w) << 16) / h  // n.16 fixed point.
       for i := start; i != stop; i += i_step:
         o := offset >> 16
         x3 := ?
-        r := rendering_.red_pixels_
-        g := rendering_.green_pixels_
-        b := rendering_.blue_pixels_
+        r := red_pixels_
+        g := green_pixels_
+        b := blue_pixels_
         if auto_crop:
           if orientation == ORIENTATION_0:
             x3 = x2 - o
@@ -411,6 +335,95 @@ class GradientElement extends ResizableElement:
           canvas.rgb_pixmap x3 (i + y2) --r=r --g=g --b=b --source_width=w --orientation=orientation
         offset += step
 
+  /// Returns a list of quadruples of the form starting-percent ending-percent start-color end-color.
+  static extract_ranges_ specifiers/List -> List:
+    result := []
+    for i := -1; i < specifiers.size; i++:
+      from := i < 0 ? 0 : specifiers[i].percent
+      to := i >= specifiers.size - 1 ? 100 : specifiers[i + 1].percent
+      if to != from:
+        from_color := specifiers[max i 0].color
+        to_color := specifiers[min (i + 1) (specifiers.size - 1)].color
+        result.add [from, to, from_color, to_color]
+    return result
+
+  static get_colors range/List h/int [block] -> none:
+    from_y := range[0] * h / 100
+    to_y := range[1] * h / 100
+    if to_y == from_y: return
+    divisor := to_y - from_y
+    from_color := range[2]
+    // Use 8.16 fixed point arithmetic to avoid floating point.
+    r := from_color & 0xff0000
+    g := (from_color & 0xff00) << 8
+    b := (from_color & 0xff) << 16
+    to_color := range[3]
+    to_r := to_color & 0xff0000
+    to_g := (to_color & 0xff00) << 8
+    to_b := (to_color & 0xff) << 16
+    step_r := (to_r - r) / divisor
+    step_g := (to_g - g) / divisor
+    step_b := (to_b - b) / divisor
+    for y := from_y; y < to_y; y++:
+      block.call y (r >> 16) (g >> 16) (b >> 16)
+      r += step_r
+      g += step_g
+      b += step_b
+
+/**
+GradientElements are similar to CSS linear gradients and SVG gradients.
+They are given a list of $GradientSpecifier, each of which has a color and
+  a percentage, indicating where in the gradient the color should appear.
+  The specifiers should be ordered in increasing order of percentage.
+Angles are as in CSS, with 0 degrees being up and 90 degrees being to the right
+  (this is different from text orientations, which go anti-clockwise).
+See https://cssgradient.io/ for a visual explanation and playground for CSS
+  gradients.
+Example:
+```
+  gradient = GradientElement --w=200 --h=100 --angle=45
+      --specifiers=[
+          GradientSpecifier --color=0xff0000 10,    // Red from 0-10%, red-to-green from 10-50%.
+          GradientSpecifier --color=0x00ff00 50,    // Green-to-blue from 50-90%.
+          GradientSpecifier --color=0x0000ff 90,    // Blue from 90-100%.
+      ]
+  display.add gradient
+```
+*/
+class GradientElement extends ResizableElement:
+  gradient_/Gradient := ?
+  specification_/GradientSpecification_? := null
+  rendering_/GradientRendering_? := null
+
+  constructor --x/int?=null --y/int?=null --w/int?=null --h/int?=null --gradient/Gradient:
+    gradient_ = gradient
+    super --x=x --y=y --w=w --h=h
+    rendering_ = null
+
+  gradient= gradient/Gradient -> none:
+    if gradient != gradient_:
+      invalidate
+      gradient_ = gradient
+      rendering_ = null
+
+  gradient -> Gradient:
+    return gradient_
+
+  w= value/int -> none:
+    super = value
+    rendering_ = null
+
+  h= value/int -> none:
+    super = value
+    rendering_ = null
+
+  draw canvas/Canvas -> none:
+    if not (x and y and w and h): return
+    if not canvas.supports_8_bit: throw "UNSUPPORTED"
+    if not rendering_: rendering_ = GradientRendering_.get w h gradient_
+    rendering_.draw canvas x y
+
+
 class FilledRectangleElement extends RectangleElement:
   constructor --x/int?=null --y/int?=null --w/int?=null --h/int?=null --color/int?=null:
     super --x=x --y=y --w=w --h=h --color=color