Wasm build fixes

ports/wasm/js/display.mjs

@@ -27,8 +27,13 @@ export class Display {
             ? this._ctx.createImageData(this._fbWidth, this._fbHeight)
             : null;
 
-        // Scale canvas to match displayio
+        // Match the canvas to the framebuffer. The backing-store resolution
+        // (width/height attributes) MUST equal the framebuffer, else
+        // putImageData() of a fbWidth×fbHeight ImageData is clipped to the
+        // canvas default (300×150). CSS width/height then scale it for display.
         if (canvas) {
+            canvas.width = this._fbWidth;
+            canvas.height = this._fbHeight;
             canvas.style.width = this._fbWidth + 'px';
             canvas.style.height = this._fbHeight + 'px';
         }

py/compile.c

@@ -103,7 +103,11 @@ static const emit_method_table_t *emit_native_table[] = {
     &emit_native_xtensa_method_table,
     &emit_native_xtensawin_method_table,
     &emit_native_rv32_method_table,
+    #if MICROPY_EMIT_WASM
     &emit_native_wasm_method_table,
+    #else
+    NULL, // wasm native emitter is a PORT feature (needs mp_wasm_compile_native); absent in host mpy-cross
+    #endif
     &emit_native_debug_method_table,
 };
 

requirements-dev.txt

@@ -31,6 +31,10 @@ cryptography
 minify_html
 jsmin
 
+# for the wasm port's display-resource generation (tools/gen_display_resources.py)
+huffman
+adafruit-circuitpython-bitmap-font
+
 # for Silicon Labs Configurator (SLC)
 websockets
 colorama

tools/gen_display_resources.py

@@ -29,10 +29,26 @@
 class BitmapStub:
     def __init__(self, width, height, color_depth):
         self.width = width
-        self.rows = [b""] * height
+        self.height = height
+        self._stride = (width + 7) // 8            # bytes per row, MSB-first byte-packed
+        self._buf = bytearray(self._stride * height)
 
-    def _load_row(self, y, row):
-        self.rows[y] = bytes(row)
+    def _load_row(self, y, row):                   # old bitmap_font API (row = packed bytes)
+        b = bytes(row)
+        self._buf[y * self._stride:y * self._stride + self._stride] = b[:self._stride]
+
+    def __setitem__(self, index, value):           # new bitmap_font API: flat y*width+x -> 0/1
+        y, x = divmod(index, self.width)
+        off = y * self._stride + (x >> 3)
+        if value:
+            self._buf[off] |= 1 << (7 - (x & 7))
+        else:
+            self._buf[off] &= ~(1 << (7 - (x & 7))) & 0xFF
+
+    @property
+    def rows(self):
+        s = self._stride
+        return [bytes(self._buf[y * s:y * s + s]) for y in range(self.height)]
 
 
 f = bitmap_font.load_font(args.font, BitmapStub)
@@ -69,7 +85,7 @@ def _load_row(self, y, row):
         filtered_characters = filtered_characters.replace(c, "")
         continue
     g = f.get_glyph(ord(c))
-    if g["shift"][1] != 0:
+    if g.shift_y != 0:
         raise RuntimeError("y shift")
 
 if missing > 0:
@@ -83,10 +99,10 @@ def _load_row(self, y, row):
 
 for x, c in enumerate(filtered_characters):
     g = f.get_glyph(ord(c))
-    start_bit = x * tile_x + g["bounds"][2]
-    start_y = (tile_y - 2) - (g["bounds"][1] + g["bounds"][3])
-    for y, row in enumerate(g["bitmap"].rows):
-        for i in range(g["bounds"][0]):
+    start_bit = x * tile_x + g.dx
+    start_y = (tile_y - 2) - (g.height + g.dy)
+    for y, row in enumerate(g.bitmap.rows):
+        for i in range(g.width):
             byte = i // 8
             bit = i % 8
             if row[byte] & (1 << (7 - bit)) != 0: