C#控件picturebox實現(xiàn)圖像拖拽和縮放
本文實例為大家分享了C# picturebox實現(xiàn)圖像拖拽和縮放的具體代碼,供大家參考,具體內(nèi)容如下
1.核心步驟:
①新建Point類型全局變量mouseDownPoint,記錄拖拽過程中鼠標(biāo)位置;
②MouseDown事件記錄Cursor位置;
③MouseMove事件計算移動矢量,并更新pictureBox1.Location。
代碼:
private void pictureBox1_MouseDown(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { mouseDownPoint.X = Cursor.Position.X; //記錄鼠標(biāo)左鍵按下時位置 mouseDownPoint.Y = Cursor.Position.Y; isMove = true; pictureBox1.Focus(); //鼠標(biāo)滾輪事件(縮放時)需要picturebox有焦點 } } private void pictureBox1_MouseUp(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { isMove = false; } } private void pictureBox1_MouseMove(object sender, MouseEventArgs e) { pictureBox1.Focus(); //鼠標(biāo)在picturebox上時才有焦點,此時可以縮放 if (isMove) { int x, y; //新的pictureBox1.Location(x,y) int moveX, moveY; //X方向,Y方向移動大小。 moveX = Cursor.Position.X - mouseDownPoint.X; moveY = Cursor.Position.Y - mouseDownPoint.Y; x = pictureBox1.Location.X + moveX; y = pictureBox1.Location.Y + moveY; pictureBox1.Location = new Point(x, y); mouseDownPoint.X = Cursor.Position.X; mouseDownPoint.Y = Cursor.Position.Y; } } private void panel2_MouseDown(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { mouseDownPoint.X = Cursor.Position.X; //記錄鼠標(biāo)左鍵按下時位置 mouseDownPoint.Y = Cursor.Position.Y; isMove = true; } } private void panel2_MouseUp(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { isMove = false; } } private void panel2_MouseMove(object sender, MouseEventArgs e) { panel2.Focus(); //鼠標(biāo)不在picturebox上時焦點給別的控件,此時無法縮放 if (isMove) { int x, y; //新的pictureBox1.Location(x,y) int moveX, moveY; //X方向,Y方向移動大小。 moveX = Cursor.Position.X - mouseDownPoint.X; moveY = Cursor.Position.Y - mouseDownPoint.Y; x = pictureBox1.Location.X + moveX; y = pictureBox1.Location.Y + moveY; pictureBox1.Location = new Point(x, y); mouseDownPoint.X = Cursor.Position.X; mouseDownPoint.Y = Cursor.Position.Y; } }
2.圖像縮放
核心思想:利用picturebox的zoom模式,根據(jù)圖像顯示大小更改picturebox大小,記錄鼠標(biāo)位置補償縮放位移,實現(xiàn)錨點縮放,即以鼠標(biāo)位置為中心進行縮放。
zoomstep --- 自己定義滾輪滑動縮放大小
代碼:
//實現(xiàn)錨點縮放(以鼠標(biāo)所指位置為中心縮放); //步驟: //①先改picturebox長寬,長寬改變量一樣; //②獲取縮放后picturebox中實際顯示圖像的長寬,這里長寬是不一樣的; //③將picturebox的長寬設(shè)置為顯示圖像的長寬; //④補償picturebox因縮放產(chǎn)生的位移,實現(xiàn)錨點縮放。 // 注釋:為啥要②③步?由于zoom模式的機制,把picturebox背景設(shè)為黑就知道為啥了。 //這里需要獲取zoom模式下picturebox所顯示圖像的大小信息,添加 using System.Reflection; //pictureBox1_MouseWheel事件沒找到。。。手動添加,別忘在Form1.Designer.cs的“Windows 窗體設(shè)計器生成的代碼”里加入: //this.pictureBox1.MouseWheel += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseWheel)。 private void pictureBox1_MouseWheel(object sender, MouseEventArgs e) { int x = e.Location.X; int y = e.Location.Y; int ow = pictureBox1.Width; int oh = pictureBox1.Height; int VX, VY; //因縮放產(chǎn)生的位移矢量 if (e.Delta > 0) //放大 { //第①步 pictureBox1.Width += zoomStep; pictureBox1.Height += zoomStep; //第②步 PropertyInfo pInfo = pictureBox1.GetType().GetProperty("ImageRectangle", BindingFlags.Instance | BindingFlags.NonPublic); Rectangle rect = (Rectangle)pInfo.GetValue(pictureBox1, null); //第③步 pictureBox1.Width = rect.Width; pictureBox1.Height = rect.Height; } if (e.Delta < 0) //縮小 { //防止一直縮成負(fù)值 if (pictureBox1.Width < myBmp.Width / 10) return; pictureBox1.Width -= zoomStep; pictureBox1.Height -= zoomStep; PropertyInfo pInfo = pictureBox1.GetType().GetProperty("ImageRectangle", BindingFlags.Instance | BindingFlags.NonPublic); Rectangle rect = (Rectangle)pInfo.GetValue(pictureBox1, null); pictureBox1.Width = rect.Width; pictureBox1.Height = rect.Height; } //第④步,求因縮放產(chǎn)生的位移,進行補償,實現(xiàn)錨點縮放的效果 VX = (int)((double)x * (ow - pictureBox1.Width) / ow); VY = (int)((double)y * (oh - pictureBox1.Height) / oh); pictureBox1.Location = new Point(pictureBox1.Location.X + VX, pictureBox1.Location.Y + VY); }
以上就是本文的全部內(nèi)容,希望對大家的學(xué)習(xí)有所幫助,也希望大家多多支持腳本之家。
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