performPaint method

@override void performPaint(Buffer buffer, Offset offset)

Hook for subclasses to implement actual painting.

Implementation

@override
void performPaint(Buffer buffer, Offset offset) {
  final viewport = Viewport(
    buffer,
    Rect(offset.dx, offset.dy, size.width, size.height),
  );
  final display = widget as SevenSegmentDisplay;
  if (size.width <= 0 || size.height < 5) return;

  final activeSt = Style(foreground: display.activeColor);
  final inactiveSt = Style(foreground: display.inactiveColor);

  int offsetX = 0;
  for (int i = 0; i < display.value.length; i++) {
    final char = display.value[i];
    final matrix =
        SevenSegmentDisplay._digits[char] ?? SevenSegmentDisplay._digits[' '];

    if (matrix != null) {
      for (int y = 0; y < 5; y++) {
        for (int x = 0; x < 5; x++) {
          if (offsetX + x < size.width && y < size.height) {
            final active = matrix[y][x] == 1;
            viewport.writeString(
              offsetX + x,
              y,
              '█',
              active ? activeSt : inactiveSt,
            );
          }
        }
      }
      offsetX += 6; // 5 width + 1 spacing
    }
  }
}