Merge branch 'erik-750-slider' into erik-800-transform-fields

CMakeLists.txt

@@ -4,10 +4,8 @@
 
 cmake_minimum_required(VERSION 3.22)
 
-# Avoid testing the C compiler.
-PROJECT(MakeTags NONE)
-
-project(cli)
+# NONE means skip testing the C compiler.
+project(pixel_display NONE)
 
 enable_testing()
 add_subdirectory(tests)

src/pixel_display.toit

@@ -322,18 +322,6 @@ abstract class PixelDisplay implements Window:
 
   // Clean determines if we should clean or draw the dirty area.
   update_frame_buffer clean/bool refresh_dimensions -> none:
-    width_target := 64
-    width := ?
-    max_height := ?
-    while true:
-      width = min driver_.width (width_target - 8)
-      max_height = max
-          round_down (max_canvas_height_ width) y_rounding_
-          y_rounding_
-      if max_height < driver_.height: break
-      if width >= driver_.width: break
-      width_target += width_target
-
     redraw := : | l t r b |
       if clean:
         clean_rect_ l t r b
@@ -368,6 +356,26 @@ abstract class PixelDisplay implements Window:
         redraw.call l (t + h) r b
         return
 
+    // Start with a width target of (slightly less than) 64 pixels, but ask
+    // the canvas how tall the patches can be. It will normally try pick a
+    // height that keeps things inside a 4k page.
+    width_target := 64
+    width := ?
+    max_height := ?
+    while true:
+      // Canvas sizes must often be slightly less than 4k in order to fit into
+      // a 4k page with object header overhead. By subtracting 8 here we get nice
+      // heights like 8, 16, 24, 32 that almost fill the max canvas size.
+      width = min driver_.width (width_target - 8)
+      max_height = max
+          round_down (max_canvas_height_ width) y_rounding_
+          y_rounding_
+      // Don't widen any more if the patches are already too flat to fill the full height.
+      if max_height <= driver_.height: break
+      // Don't widen any more if the patches already cover the whole width.
+      if width >= driver_.width: break
+      width_target += width_target
+
     // The algorithm below requires that x aligns with 8 pixels, the resolution
     // of the dirty map.
     start_x := round_down (max 0 dirty_left_) 8

tests/png-visualizer.toit

@@ -58,8 +58,8 @@ class SeveralColorPngVisualizer extends PngVisualizingDriver_:
 abstract class PngVisualizingDriver_ extends AbstractDriver:
   width /int ::= ?
   height /int ::= ?
-  width_ /int := 0  // Rounded up to a multiple of 8.
-  height_ /int := 0  // Rounded up to a multiple of 8.
+  width_ := 0  // Rounded up depending on the bit depth.
+  height_ := 0  // Rounded up depending on the bit depth.
   outline_buffer_ /ByteArray? := null
   buffer_ /ByteArray := #[]
   temp_buffer_/ByteArray := #[]
@@ -73,7 +73,6 @@ abstract class PngVisualizingDriver_ extends AbstractDriver:
 
   constructor .width .height basename/string --.outline/int?=null:
     png_basename_ = basename
-    ///
     width_ = round_up width x_rounding
     height_ = round_up height y_rounding
     buffer_ = ByteArray
@@ -200,11 +199,13 @@ abstract class PngVisualizingDriver_ extends AbstractDriver:
   draw_byte_outline_ outline/int pixels/ByteArray patch_width/int --dotted=false -> none:
     bottom_left := pixels.size - patch_width
     // Dotted line along top and bottom.
-    for x := 0; x < patch_width; x += dotted ? 2 : 1:
+    x_step := dotted ? 2 : 1
+    for x := 0; x < patch_width; x += x_step:
       pixels[x] = outline
       pixels[bottom_left + x] = outline
     // Dotted line along left and right.
-    for y := 0; y < pixels.size; y += patch_width * (dotted ? 2 : 1):
+    y_step := patch_width * (dotted ? 2 : 1)
+    for y := 0; y < pixels.size; y += y_step:
       pixels[y] = outline
       pixels[y + patch_width - 1] = outline