C#取屏幕顏色

忘是亡心i 2022-08-25 12:58 219阅读 0赞

C\#取屏幕顏色

1.原理  
調用API取得屏幕上一個象素大小的位圖,這個位圖的底色就是鼠標所在點的屏幕顏色.

2.實現  
\--1.先聲明API

\[DllImport( " gdi32.dll " )\]  
 private  static  extern  bool  BitBlt(  
IntPtr hdcDest,  //  目標設備的句柄    
  int  nXDest,  //  目標對像的左上角的X坐標    
  int  nYDest,  //  目標對像的左上角的X坐標    
  int  nWidth,  //  目標對像的矩形的寬度    
  int  nHeight,  //  目標對像的矩形的長度    
  IntPtr hdcSrc,  //  源設備的句柄    
  int  nXSrc,  //  源對像的左上角的X坐標    
  int  nYSrc,  //  源對像的左上角的X坐標    
  int  dwRop  //  光柵的操作值    
  );  
  
\[DllImport( " gdi32.dll " )\]  
 private  static  extern  IntPtr CreateDC(  
 string  lpszDriver,  //  驅動名稱    
  string  lpszDevice,  //  設備名稱    
  string  lpszOutput,  //  無用，可以設定位"NULL"    
  IntPtr lpInitData  //  任意的打印機數據    
  );

\--2.編寫取色函數

private  Color GetArgb()  
\{  
Color rtnColor;  
 //  創建顯示器的DC    
  IntPtr hdlDisplay  =  CreateDC( " DISPLAY " ,  null ,  null , IntPtr.Zero);  
 //  從指定設備的句柄創建新的 Graphics 對像    
  Graphics gfxDisplay  =  Graphics.FromHdc(hdlDisplay);  
 //  創建隻有一個像素大小的 Bitmap 對像    
  Bitmap bmp  =  new  Bitmap( 1 ,  1 , gfxDisplay);  
 //  從指定 Image 對像創建新的 Graphics 對像    
  Graphics gfxBmp  =  Graphics.FromImage(bmp);  
 //  獲得屏幕的句柄    
  IntPtr hdlScreen  =  gfxDisplay.GetHdc();  
 //  獲得位圖的句柄    
  IntPtr hdlBmp  =  gfxBmp.GetHdc();  
 //  把當前屏幕中鼠標指針所在位置的一個像素拷貝到位圖中    
  BitBlt(hdlBmp,  0 ,  0 ,  1 ,  1 , hdlScreen, MousePosition.X, MousePosition.Y,  13369376 );  
 //  釋放屏幕句柄    
  gfxDisplay.ReleaseHdc(hdlScreen);  
 //  釋放位圖句柄    
  gfxBmp.ReleaseHdc(hdlBmp);  
rtnColor  =  bmp.GetPixel( 0 ,  0 );  //  獲取像素的顏色    
  bmp.Dispose();  //  釋放 bmp 所使用的資源    
  return  rtnColor;  
\}

3.触發事件  
這里采用時間触發方式.  
Bug:我認為采用鼠標移動時触發更合适.

this .tmr.Tick  \+=  new  System.EventHandler( this .tmr\_Tick);  
 private  void  tmr\_Tick( object  sender, EventArgs e)  
\{  
lblColor.BackColor = GetArgb();  
txtArgb.Text  =  lblColor.BackColor.R.ToString()  \+  " , "  \+  lblColor.BackColor.G.ToString()  \+  " , "  \+  lblColor.BackColor.B.ToString();  
  
\}

4.調整顯示窗体  
當鼠標移到當前窗体時,窗体需要移開.  
先聲明變量:

//  桌面工作區的尺寸    
  Size workingArea;  
 //  Form 的初始位置和在左下角，右下角的位置    
  Point formLoc, ptLeftBottom, ptRightBottom;

初始化變量:

Rectangle rect  =  SystemInformation.WorkingArea;  
workingArea  =  new  Size(rect.Width, rect.Height);  
ptLeftBottom  =  new  Point( 0 , workingArea.Height  \-  this .Height);  
ptRightBottom  =  new  Point(workingArea.Width  \-  this .Width, workingArea.Height  \-  this .Height);

触發事件:

this .MouseEnter  \+=  new  System.EventHandler( this .Form1\_MouseEnter);  
 private  void  Form1\_MouseEnter( object  sender, EventArgs e)  
\{  
 if  ( this .Location  ==  ptLeftBottom)  // 窗體在左下角    
  \{  
 this .Location  =  ptRightBottom;  
\}  
 else  if  ( this .Location  ==  ptRightBottom)  //  窗體在右下角    
  \{  
 this .Location  =  ptLeftBottom;  
\}  
\}

3.全部源碼,可運行

using  System;  
 using  System.Drawing;  
 using  System.Collections;  
 using  System.ComponentModel;  
 using  System.Windows.Forms;  
 using  System.Data;  
 using  System.Drawing.Imaging;  
 using  System.Runtime.InteropServices;  
  
 namespace  PrintDemo  
\{  
 ///  <summary>   
 ///  Form1 的摘要說明。  
 ///  </summary>    
  public  class  Form1 : System.Windows.Forms.Form  
\{  
 //  桌面工作區的尺寸    
  Size workingArea;  
 //  Form 的初始位置和在左下角，右下角的位置    
  Point formLoc, ptLeftBottom, ptRightBottom;  
  
 private  System.Windows.Forms.Label lblColor;  
 private  System.Windows.Forms.TextBox txtArgb;  
 private  System.Windows.Forms.Timer tmr;  
 private  System.Windows.Forms.ToolTip tip;  
 private  System.ComponentModel.IContainer components;  
  
 public  Form1()  
\{  
InitializeComponent();  
  
 this .FormBorderStyle  =  FormBorderStyle.FixedToolWindow;  
 this .StartPosition  =  FormStartPosition.CenterScreen;  
  
Rectangle rect  =  SystemInformation.WorkingArea;  
workingArea  =  new  Size(rect.Width, rect.Height);  
ptLeftBottom  =  new  Point( 0 , workingArea.Height  \-  this .Height);  
ptRightBottom  =  new  Point(workingArea.Width  \-  this .Width,  
workingArea.Height  \-  this .Height);  
  
String tipMsg  =  " 在窗體空白處雙擊鼠標左鍵開始取色，按ESC鍵確定顏色 " ;  
tip.SetToolTip( this , tipMsg);  
tip.SetToolTip(lblColor, tipMsg);  
tip.SetToolTip(txtArgb, tipMsg);  
\}  
  
 ///  <summary>   
 ///  清理所有正在使用的資源。  
 ///  </summary>    
  protected  override  void  Dispose( bool  disposing)  
\{  
 if  (disposing)  
\{  
 if  (components  !=  null )  
\{  
components.Dispose();  
\}  
\}  
 base .Dispose(disposing);  
\}  
  
 \#region  Windows Form Designer generated code   
 ///  <summary>   
 ///  設計器支持所需的方法 - 不要使用代碼編輯器修改  
 ///  此方法的內容。  
 ///  </summary>    
  private  void  InitializeComponent()  
\{  
 this .components  =  new  System.ComponentModel.Container();  
 this .lblColor  =  new  System.Windows.Forms.Label();  
 this .tmr  =  new  System.Windows.Forms.Timer( this .components);  
 this .txtArgb  =  new  System.Windows.Forms.TextBox();  
 this .tip  =  new  System.Windows.Forms.ToolTip( this .components);  
 this .SuspendLayout();  
 //   
 //  lblColor  
 //    
  this .lblColor.BorderStyle  =  System.Windows.Forms.BorderStyle.FixedSingle;  
 this .lblColor.Location  =  new  System.Drawing.Point( 8 ,  8 );  
 this .lblColor.Name  =  " lblColor " ;  
 this .lblColor.Size  =  new  System.Drawing.Size( 120 ,  23 );  
 this .lblColor.TabIndex  =  0 ;  
 //   
 //  tmr  
 //    
  this .tmr.Tick  \+=  new  System.EventHandler( this .tmr\_Tick);  
 //   
 //  txtArgb  
 //    
  this .txtArgb.BorderStyle  =  System.Windows.Forms.BorderStyle.FixedSingle;  
 this .txtArgb.Font  =  new  System.Drawing.Font( " Arial " ,  10.5F , System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)( 0 )));  
 this .txtArgb.Location  =  new  System.Drawing.Point( 8 ,  40 );  
 this .txtArgb.Name  =  " txtArgb " ;  
 this .txtArgb.Size  =  new  System.Drawing.Size( 120 ,  24 );  
 this .txtArgb.TabIndex  =  1 ;  
 this .txtArgb.Text  =  "" ;  
 this .txtArgb.KeyPress  \+=  new  System.Windows.Forms.KeyPressEventHandler( this .txtArgb\_KeyPress);  
 //   
 //  Form1  
 //    
  this .AutoScaleBaseSize  =  new  System.Drawing.Size( 6 ,  14 );  
 this .ClientSize  =  new  System.Drawing.Size( 136 ,  69 );  
 this .Controls.Add( this .txtArgb);  
 this .Controls.Add( this .lblColor);  
 this .Name  =  " Form1 " ;  
 this .Text  =  " 屏幕取色(upto) " ;  
 this .DoubleClick  \+=  new  System.EventHandler( this .Form1\_DoubleClick);  
 this .MouseEnter  \+=  new  System.EventHandler( this .Form1\_MouseEnter);  
 this .ResumeLayout( false );  
  
\}  
 \#endregion   
  
  
\[DllImport( " gdi32.dll " )\]  
 private  static  extern  bool  BitBlt(  
IntPtr hdcDest,  //  目標設備的句柄    
  int  nXDest,  //  目標對像的左上角的X坐標    
  int  nYDest,  //  目標對像的左上角的X坐標    
  int  nWidth,  //  目標對像的矩形的寬度    
  int  nHeight,  //  目標對像的矩形的長度    
  IntPtr hdcSrc,  //  源設備的句柄    
  int  nXSrc,  //  源對像的左上角的X坐標    
  int  nYSrc,  //  源對像的左上角的X坐標    
  int  dwRop  //  光柵的操作值    
  );  
  
\[DllImport( " gdi32.dll " )\]  
 private  static  extern  IntPtr CreateDC(  
 string  lpszDriver,  //  驅動名稱    
  string  lpszDevice,  //  設備名稱    
  string  lpszOutput,  //  無用，可以設定位"NULL"    
  IntPtr lpInitData  //  任意的打印機數據    
  );  
  
 private  void  Form1\_DoubleClick( object  sender, EventArgs e)  
\{  
formLoc  =  this .Location;  
 this .Location  =  ptRightBottom;  
 this .TopMost  =  true ;  
tmr.Enabled  =  true ;  
\}  
  
 private  Color GetArgb()  
\{  
Color rtnColor;  
 //  創建顯示器的DC    
  IntPtr hdlDisplay  =  CreateDC( " DISPLAY " ,  null ,  null , IntPtr.Zero);  
 //  從指定設備的句柄創建新的 Graphics 對像    
  Graphics gfxDisplay  =  Graphics.FromHdc(hdlDisplay);  
 //  創建隻有一個像素大小的 Bitmap 對像    
  Bitmap bmp  =  new  Bitmap( 1 ,  1 , gfxDisplay);  
 //  從指定 Image 對像創建新的 Graphics 對像    
  Graphics gfxBmp  =  Graphics.FromImage(bmp);  
 //  獲得屏幕的句柄    
  IntPtr hdlScreen  =  gfxDisplay.GetHdc();  
 //  獲得位圖的句柄    
  IntPtr hdlBmp  =  gfxBmp.GetHdc();  
 //  把當前屏幕中鼠標指針所在位置的一個像素拷貝到位圖中    
  BitBlt(hdlBmp,  0 ,  0 ,  1 ,  1 , hdlScreen, MousePosition.X, MousePosition.Y,  13369376 );  
 //  釋放屏幕句柄    
  gfxDisplay.ReleaseHdc(hdlScreen);  
 //  釋放位圖句柄    
  gfxBmp.ReleaseHdc(hdlBmp);  
rtnColor  =  bmp.GetPixel( 0 ,  0 );  //  獲取像素的顏色    
  bmp.Dispose();  //  釋放 bmp 所使用的資源    
  return  rtnColor;  
\}  
 private  void  tmr\_Tick( object  sender, EventArgs e)  
\{  
lblColor.BackColor = GetArgb();  
txtArgb.Text  =  lblColor.BackColor.R.ToString()  \+  " , "  \+  lblColor.BackColor.G.ToString()  \+  " , "  \+  lblColor.BackColor.B.ToString();  
  
\}  
  
 private  void  txtArgb\_KeyPress( object  sender, KeyPressEventArgs e)  
\{  
 //  當按下ESC鍵時，確定所取的顏色ARGB值  
 //  Bug：隻有當窗體處於激活狀態時才有效,以後要是能點一下右鍵就可以就好了或者換成熱鍵觸發.   
  if  (e.KeyChar  ==  ( char )Keys.Escape)  
\{  
tmr.Enabled  =  false ;  
 this .Location  =  formLoc;  
 this .TopMost  =  false ;  
txtArgb.SelectAll();  
\}  
\}  
  
 private  void  Form1\_MouseEnter( object  sender, EventArgs e)  
\{  
 if  ( this .Location  ==  ptLeftBottom)  // 窗體在左下角    
  \{  
 this .Location  =  ptRightBottom;  
\}  
 else  if  ( this .Location  ==  ptRightBottom)  //  窗體在右下角    
  \{  
 this .Location  =  ptLeftBottom;  
\}  
\}  
\}  
\}