paint method

@override void paint(PaintingContext context, Offset offset)

Paint this render object into the given context at the given offset.

Subclasses should override this method to provide a visual appearance for themselves. The render object's local coordinate system is axis-aligned with the coordinate system of the context's canvas and the render object's local origin (i.e, x=0 and y=0) is placed at the given offset in the context's canvas.

Do not call this function directly. If you wish to paint yourself, call markNeedsPaint instead to schedule a call to this function. If you wish to paint one of your children, call PaintingContext.paintChild on the given context.

When painting one of your children (via a paint child function on the given context), the current canvas held by the context might change because draw operations before and after painting children might need to be recorded on separate compositing layers.

Implementation

@override
void paint(PaintingContext context, Offset offset) {
  if (enableWebFProfileTracking) {
    WebFProfiler.instance.startTrackPaint(this);
  }
  assert(() {
    if (debugRepaintTextRainbowEnabled) {
      final Paint paint = Paint()..color = debugCurrentRepaintColor.toColor();
      context.canvas.drawRect(offset & size, paint);
    }
    return true;
  }());

  if (_needsClipping) {
    final Rect bounds = offset & size;
    if (_overflowShader != null) {
      // This layer limits what the shader below blends with to be just the
      // text (as opposed to the text and its background).
      context.canvas.saveLayer(bounds, Paint());
    } else {
      context.canvas.save();
    }
    context.canvas.clipRect(bounds);
  }

  if (lineHeight != null) {
    // Adjust text paint offset of each line according to line-height.
    for (int i = 0; i < _lineTextPainters.length; i++) {
      // _lineTextPainters and _lineOffset may not have the same length in some edge cases
      // cause _lineTextPainters is computed from [getBoxesForSelection] api while
      // _lineOffset is computed from [computeLineMetrics] api.
      // Add protection here to prevent access the overflow index of _lineOffset list.
      if (i >= _lineOffset.length) continue;

      TextPainter _lineTextPainter = _lineTextPainters[i];
      Offset lineOffset = Offset(offset.dx, offset.dy + _lineOffset[i]);
      _lineTextPainter.paint(context.canvas, lineOffset);
    }
  } else {
    _textPainter.paint(context.canvas, offset);
  }

  if (_needsClipping) {
    if (_overflowShader != null) {
      context.canvas.translate(offset.dx, offset.dy);
      final Paint paint = Paint()
        ..blendMode = BlendMode.modulate
        ..shader = _overflowShader;
      context.canvas.drawRect(Offset.zero & size, paint);
    }
    context.canvas.restore();
  }

  if (enableWebFProfileTracking) {
    WebFProfiler.instance.finishTrackPaint(this);
  }
}