具有反色文本的进度条绘制方法

以下的代码解决的是当进度到一半左右，文本与图片的叠加问题。 

        public void DrawProgressBar(Graphics g, Rectangle bounds, ProgressBar bar)
        {
            Bitmap back = null, bval = null;
            if (rsMgr.Enabeld)
            {
                back = rsMgr.GetBitmap("PROGRESSBAR"); //背景图片
                bval = rsMgr.GetBitmap("PROGRESSBAR_VALUE"); //前景图片
            }
            
            //获得比例
            decimal v = bar.Value / (decimal)(bar.Maximum - bar.Minimum);
            Rectangle rect = bounds;
            rect.Inflate(-1, -1);

            if (back != null)
            {
                //绘制背景图片
                TextureBrush b = new TextureBrush(back);
                b.TranslateTransform(0, rect.Top);
                b.ScaleTransform(1, rect.Height / (float)back.Height);
                g.FillRectangle(b, rect);
                b.Dispose();
                ControlPaint.DrawBorder(g, rect, rsMgr.GetColor("BORDERCOLOR"), ButtonBorderStyle.Solid);
            }
            else
            {
                //用颜色填充
                g.FillRectangle(new SolidBrush(bar.BackColor), rect);
                ControlPaint.DrawBorder(g, rect, Color.LightGray, ButtonBorderStyle.Solid);
            }

            rect.Inflate(-2, -2);
            rect.Width = (int)(rect.Width * v);

            if (bval != null)
            {
                //绘制前景图片
                TextureBrush b = new TextureBrush(bval);
                b.TranslateTransform(0, rect.Top);
                b.ScaleTransform(1, rect.Height / (float)bval.Height);
                g.FillRectangle(b, rect);
                b.Dispose();
            }
            else
            {
                //颜色填充
                g.FillRectangle(SystemBrushes.Highlight, rect);
            }

            //输出文本
            StringFormat sf = new StringFormat();
            sf.LineAlignment = StringAlignment.Center;
            sf.Alignment = StringAlignment.Center;
            Region oldClip = g.Clip;
            if (bval != null)
            {
                //先输出整个文本
                Bitmap inb = (Bitmap)back.Clone();
                //这里将图片反转
                BitmapHelper.Invert(inb);
                TextureBrush b = new TextureBrush(inb);
                g.DrawString(bar.Text, bar.Font, b, bounds, sf);

                //剪辑后在前景范围内输出
                g.SetClip(rect);
                inb = (Bitmap)bval.Clone();
                BitmapHelper.Invert(inb);
                b = new TextureBrush(inb);
                g.DrawString(bar.Text, bar.Font, b, bounds, sf);

                b.Dispose();
                inb.Dispose();
            }
            else
            {
                g.DrawString(bar.Text, bar.Font, SystemBrushes.WindowText, bounds, sf);
                g.SetClip(rect);
                g.DrawString(bar.Text, bar.Font, SystemBrushes.HighlightText, bounds, sf);
            }
            g.SetClip(oldClip, CombineMode.Replace);
            if (back != null) back.Dispose();
            if (bval != null) bval.Dispose();
        }

效果可参见上一文章http://www.cnblogs.com/faib/archive/2009/02/10/1387824.html。