getConstraints method

BoxConstraints getConstraints()

Implementation

BoxConstraints getConstraints() {
  if (enableWebFProfileTracking) {
    WebFProfiler.instance.startTrackLayoutStep('RenderTextBox.getConstraints()');
  }

  if (renderStyle.whiteSpace == WhiteSpace.nowrap && renderStyle.effectiveTextOverflow != TextOverflow.ellipsis) {
    if (enableWebFProfileTracking) {
      WebFProfiler.instance.finishTrackLayoutStep();
    }
    return BoxConstraints();
  }

  double maxConstraintWidth = double.infinity;
  if (parent is RenderBoxModel) {
    RenderBoxModel parentRenderBoxModel = parent as RenderBoxModel;
    BoxConstraints parentConstraints = parentRenderBoxModel.constraints;

    if (parentRenderBoxModel.isScrollingContentBox && parentRenderBoxModel is! RenderFlexLayout) {
      maxConstraintWidth = (parentRenderBoxModel.parent as RenderBoxModel).constraints.maxWidth;
    } else if (parentConstraints.maxWidth == double.infinity) {
      final ParentData? parentParentData = parentRenderBoxModel.parentData;
      // Width of positioned element does not constrained by parent.
      if (parentParentData is RenderLayoutParentData && parentParentData.isPositioned) {
        maxConstraintWidth = double.infinity;
      } else {
        maxConstraintWidth = parentRenderBoxModel.renderStyle.contentMaxConstraintsWidth;
        // @FIXME: Each character in the text will be placed in a new line when remaining space of
        // parent is 0 cause word-break behavior can not be specified in flutter.
        // https://github.com/flutter/flutter/issues/61081
        // This behavior is not desirable compared to the default word-break:break-word value in the browser.
        // So we choose to not do wrapping for text in this case.
        if (maxConstraintWidth == 0) {
          maxConstraintWidth = double.infinity;
        }
      }
    } else {
      EdgeInsets borderEdge = parentRenderBoxModel.renderStyle.border;
      EdgeInsetsGeometry? padding = parentRenderBoxModel.renderStyle.padding;
      double horizontalBorderLength = borderEdge.horizontal;
      double horizontalPaddingLength = padding.horizontal;

      maxConstraintWidth = parentConstraints.maxWidth - horizontalPaddingLength - horizontalBorderLength;
    }
  }

  if (enableWebFProfileTracking) {
    WebFProfiler.instance.finishTrackLayoutStep();
  }

  // Text will not overflow from container, so it can inherit
  // constraints from parents
  return BoxConstraints(minWidth: 0, maxWidth: maxConstraintWidth, minHeight: 0, maxHeight: double.infinity);
}