textinput 属性lineThrough原理_font strikethrough offset-优快云博客

本文介绍了一种在 Flash 中实现文本下划线和删除线效果的方法。通过创建 Shape 子对象并利用 Graphics API 来绘制这些装饰线，解决了 Flash 原生不支持直接渲染这些文本装饰的问题。

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if (lineThrough || textDecoration == "underline")
            {
                // FTE doesn't render strikethroughs or underlines,
                // but it can tell us where to draw them.
                // You can't draw in a TextLine but it can have children,
                // so we create a child Shape to draw them in.

                var elementFormat:ElementFormat =
                    TextElement(textBlock.content).elementFormat;
                var fontMetrics:FontMetrics;
                if (embeddedFontContext)
                    fontMetrics = embeddedFontContext.callInContext(elementFormat.getFontMetrics, elementFormat, null);
                else
                    fontMetrics = elementFormat.getFontMetrics();

                var shape:Shape = new Shape();
                var g:Graphics = shape.graphics;
                if (lineThrough)
                {
                    g.lineStyle(fontMetrics.strikethroughThickness,
                                elementFormat.color, elementFormat.alpha);
                    g.moveTo(0, fontMetrics.strikethroughOffset);
                    g.lineTo(textLine.textWidth, fontMetrics.strikethroughOffset);
                }
                if (textDecoration == "underline")
                {
                    g.lineStyle(fontMetrics.underlineThickness,
                                elementFormat.color, elementFormat.alpha);
                    g.moveTo(0, fontMetrics.underlineOffset);
                    g.lineTo(textLine.textWidth, fontMetrics.underlineOffset);
                }

                textLine.addChild(shape);
            }