在Y轴上反转绘制文本

Question

我正在编写一个可视化应用程序：它从XML中加载构建几何图形并将其绘制在屏幕上。 建筑由长方形的房间组成，其中很多 - 所以我想在他们身上画出他们的名字。

我使用this教程来翻转我的形式的Y轴，因为建筑数据存储在笛卡尔坐标。并将其全部转换为经典的Windows“y增长”系统，而绘图看起来很奇怪。
另外我需要缩放并将我的“场景”翻译为左下角。
而且，我的痛苦最后，我需要再次翻转我的文字 - 因为它也会翻转！

由于tutorial说，我需要：

1. 翻转Y轴，规模和移动场景所需位置
2. 绘制建筑几何（只是矩形）在直角坐标
3. 返回到“Y增长下经典的‘系统

但COOR”制度，规模，在此再次移动

绘制文本’文字的用餐无效！ 。
他们是从正确的位置:(

所以这是我的问题下移 - 如何计算在Windows新的文本坐标形式正确对象

void VisualizerForm_Paint(object sender, PaintEventArgs e) 
{ 
    // Setup graphics output settings 
    var g = e.Graphics; 
    g.Clear(Color.White); 
    g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; 
    g.PageUnit = GraphicsUnit.Pixel; 

    // Move coordinate system center to the bottom left corner, 
    // scale it to user-defined scale value and flip Y axis (mul it scale to -1) 
    g.ScaleTransform(m_scale, -m_scale, MatrixOrder.Append); 
    g.TranslateTransform(50, Height - 50, MatrixOrder.Append); 

    // ... Draw some complex building geometry ... 

    // Draw building room 
    var customPen = new Pen(Color.Black, 1.0f/g.DpiX); 
    var rect = new RectangleF(box.X1, box.Y1, (box.X2 - box.X1), (box.Y2 - box.Y1)); 
    g.DrawRectangle(customPen, box.X1, box.Y1, (box.X2 - box.X1), (box.Y2 - box.Y1)); 

    GraphicsState gs = g.Save(); 

    // First reset transform matrix 
    g.ResetTransform(); 
    // Then again scale and move scene, but now with classic down-incresed Y axis 
    g.ScaleTransform(m_scale, m_scale, MatrixOrder.Append); 
    g.TranslateTransform(50, Height - 50, MatrixOrder.Append); 

    // All Y coords now must be inverted :/ *sigh* 
    box.Y1 *= -1.0f; 
    box.Y2 *= -1.0f; 
    rect = new RectangleF(box.X1, box.Y1, Math.Abs(box.X2 - box.X1), Math.Abs(box.Y2 - box.Y1)); 

    // FIXME: This text is drawing in incorrect place 
    var fnt = new Font("Arial", 40f/g.DpiX, FontStyle.Bold, GraphicsUnit.Pixel); 
    g.DrawString("ID: " + box.Id, fnt, Brushes.Black, rect, stringFormat); 

    g.Restore(gs); 
} 

Answer 1

终于明白了！
下面的类在其中心绘制了一个带有指定文本的矩形 - 在Y反转的场景中。
文字自动缩放以适合实际的矩形大小。享受:)

class RectangleWithText 
{ 
    RectangleF m_extent = new RectangleF(); 
    string m_text = ""; 

    Font m_textFont = null; 
    RectangleF m_textRect = new RectangleF(); 

    public RectangleWithText(RectangleF extent, string text) 
    { 
     m_extent = extent; 
     m_text = text; 
    } 

    public void Draw(Graphics g) 
    { 
     var dashedGrayPen = new Pen(Color.Gray, 1.0f/g.DpiX) { DashStyle = DashStyle.Dash }; 
     var brownPen = new Pen(Color.Brown, 1.0f/g.DpiX); 

     // Draw rectangle itself 
     g.DrawRectangle(brownPen, m_extent.X, m_extent.Y, m_extent.Width, m_extent.Height); 

     // Draw text on it 
     var extentCenter = new PointF((m_extent.Left + m_extent.Right)/2, (m_extent.Bottom + m_extent.Top)/2); 
     DrawText(g, m_text, extentCenter, m_extent); 

     } 
    } 

    private void DrawText(Graphics g, string text, PointF ptStart, RectangleF extent) 
    { 
     var gs = g.Save(); 

     // Inverse Y axis again - now it grow down; 
     // if we don't do this, text will be drawn inverted 
     g.ScaleTransform(1.0f, -1.0f, MatrixOrder.Prepend); 

     if (m_textFont == null) 
     { 
      // Find the maximum appropriate text size to fix the extent 
      float fontSize = 100.0f; 
      Font fnt; 
      SizeF textSize; 
      do 
      { 
       fnt = new Font("Arial", fontSize/g.DpiX, FontStyle.Bold, GraphicsUnit.Pixel); 
       textSize = g.MeasureString(text, fnt); 
       m_textRect = new RectangleF(new PointF(ptStart.X - textSize.Width/2.0f, -ptStart.Y - textSize.Height/2.0f), textSize); 

       var textRectInv = new RectangleF(m_textRect.X, -m_textRect.Y, m_textRect.Width, m_textRect.Height); 
       if (extent.Contains(textRectInv)) 
        break; 

       fontSize -= 1.0f; 
       if (fontSize <= 0) 
       { 
        fontSize = 1.0f; 
        break; 
       } 
      } while (true); 

      m_textFont = fnt; 
     } 

     // Create a StringFormat object with the each line of text, and the block of text centered on the page 
     var stringFormat = new StringFormat() 
     { 
      Alignment = StringAlignment.Center, 
      LineAlignment = StringAlignment.Center 
     }; 
     g.DrawString(text, m_textFont, Brushes.Black, m_textRect, stringFormat); 

     g.Restore(gs); 
    } 
} 

Answer 2

试试这个：

void DrawDigonalString(Graphics G, string S, Font F, Brush B, PointF P, int Angle) 
{ 
    SizeF MySize = G.MeasureString(S, F); 
    G.TranslateTransform(P.X + MySize.Width/2, P.Y + MySize.Height/2); 
    G.RotateTransform(Angle); 
    G.DrawString(S, F, B, new PointF(-MySize.Width/2, -MySize.Height/2)); 
    G.RotateTransform(-Angle); 
    G.TranslateTransform(-P.X - MySize.Width/2, -P.Y- MySize.Height/2); 
}