[英]Screen capture without active window
我正在嘗試使用Winform或WPF Windows編寫放大鏡應用程序。 想法是將窗口拖到屏幕上的某個位置上並放大。 我知道它在商業上存在,但需要構建定制版本。 我面臨的挑戰是捕獲活動應用程序后面的屏幕圖像。 我在下面找到了捕獲屏幕圖像的代碼。 但它包含活動窗口
{
Rectangle bounds = new Rectangle(this.Location, this.Size);
Bitmap bitmap = new Bitmap(bounds.Width, bounds.Height);
Graphics g = Graphics.FromImage(bitmap);
g.CopyFromScreen(this.Location, Point.Empty, bounds.Size);
Bitmap bp2 = new Bitmap(bitmap); // local copy of image...
pictureBox1.Image = bp2;
}
添加語句以隱藏活動的應用程序可以糾正圖像捕獲,但是會引起屏幕閃爍,我想避免這種情況。 (下面的修改代碼)
{
this.StartPosition = FormStartPosition.Manual; // get current window location
Point cur = this.Location;
this.Location = new Point(-500, -500); // hide the active app off screen.
Rectangle bounds = new Rectangle(cur, this.Size);
Bitmap bitmap = new Bitmap(bounds.Width, bounds.Height);
Graphics g = Graphics.FromImage(bitmap);
g.CopyFromScreen(cur, Point.Empty, bounds.Size);
Bitmap bp2 = new Bitmap(bitmap); // local copy of image...
pictureBox1.Image = bp2;
this.Location = cur; // restore application location
}
有人可以建議在活動窗口后面捕獲屏幕區域的替代方法嗎?
謝謝。
包裝放大API非常有用。 我創建了一個Winforms控件來執行此操作。 將新類添加到您的項目中,然后粘貼以下代碼。 編譯。 將新控件從工具箱的頂部拖放到窗體上。
TrackMouse屬性控制屏幕的哪個部分被放大顯示。 設置為False時,它將放大控件覆蓋的區域,使其像放大鏡一樣起作用。 設置為True,跟隨鼠標,它將像Windows的放大鏡一樣操作。
放大倍數屬性控制放大倍數。 您已經可以使用鼠標滾輪對其進行調整。
放置的表單應將其TopMost屬性設置為True。 您可能需要修改其Region屬性,使其類似於望遠鏡。
using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;
class Magnifier : Control {
public Magnifier() {
if (!MagInitialize()) throw new NotSupportedException();
timer = new Timer { Interval = 45 };
timer.Tick += (o, ea) => { if (trackMouse) setSource(false); else Invalidate(); };
}
[DefaultValue(false)]
public bool TrackMouse {
get { return trackMouse; }
set { trackMouse = value; setSource(false); }
}
[DefaultValue(2.0f)]
public float Magnification {
get { return magnification; }
set { magnification = Math.Max(1, value); setSource(true); }
}
protected override CreateParams CreateParams {
get {
var cp = base.CreateParams;
if (!this.DesignMode) {
cp.ClassName = "Magnifier";
//cp.Style |= MS_SHOWMAGNIFIEDCURSOR;
this.SetStyle(ControlStyles.UserPaint, true);
}
return cp;
}
}
protected override void OnHandleCreated(EventArgs e) {
base.OnHandleCreated(e);
if (!this.DesignMode) {
setSource(true);
this.FindForm().LocationChanged += ParentLocationChanged;
timer.Start();
}
}
protected override void Dispose(bool disposing) {
if (disposing) {
var frm = this.FindForm();
if (frm != null) frm.LocationChanged -= ParentLocationChanged;
timer.Dispose();
MagUninitialize();
}
base.Dispose(disposing);
}
private void ParentLocationChanged(object sender, EventArgs e) {
if (!trackMouse) setSource(false);
}
protected override void OnSizeChanged(EventArgs e) {
setSource(false);
base.OnSizeChanged(e);
}
protected override void OnMouseWheel(MouseEventArgs e) {
this.Magnification += e.Delta / 100f;
((HandledMouseEventArgs)e).Handled = true;
}
private void setSource(bool newmag) {
if (!this.IsHandleCreated || this.DesignMode) return;
if (newmag) {
var xform = new MAGTRANSFORM();
xform.v11 = xform.v22 = magnification;
xform.v33 = 1.0f;
MagSetWindowTransform(this.Handle, ref xform);
}
Point center;
if (trackMouse) center = Cursor.Position;
else {
var rc = this.RectangleToScreen(this.Bounds);
center = new Point(rc.Left + rc.Width / 2, rc.Top + rc.Height / 2);
}
var scr = Screen.FromPoint(center);
var rect = new RECT();
rect.left = Math.Max(scr.Bounds.Left, center.X - (int)(this.Width / magnification / 2));
rect.top = Math.Max(scr.Bounds.Top, center.Y - (int)(this.Height / magnification / 2));
rect.right = rect.left + (int)(this.Width / magnification);
if (rect.right > scr.Bounds.Right) {
rect.right = scr.Bounds.Right;
rect.left = rect.right - (int)(this.Width / magnification);
}
rect.bottom = center.Y + (int)(this.Height / magnification);
if (rect.bottom > scr.Bounds.Bottom) {
rect.bottom = scr.Bounds.Bottom;
rect.top = rect.bottom - (int)(this.Height / magnification);
}
MagSetWindowSource(this.Handle, ref rect);
this.Invalidate();
}
private Timer timer;
private bool trackMouse;
private float magnification = 2.0f;
private struct RECT {
public int left, top, right, bottom;
}
private struct MAGTRANSFORM {
public float v11, v12, v13;
public float v21, v22, v23;
public float v31, v32, v33;
}
[DllImport("magnification.dll")]
private static extern bool MagInitialize();
[DllImport("magnification.dll")]
private static extern bool MagUninitialize();
[DllImport("magnification.dll")]
private static extern bool MagSetWindowSource(IntPtr hWnd, ref RECT rc);
[DllImport("magnification.dll")]
private static extern bool MagSetWindowTransform(IntPtr hWnd, ref MAGTRANSFORM xform);
private const int MS_SHOWMAGNIFIEDCURSOR = 1;
private const int MS_CLIPAROUNDCURSOR = 2;
private const int MS_INVERTCOLORS = 4;
}
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