我要评论很简单，就是先全屏截图，然后再按需要裁剪就可以了。
所以，首先要获取桌面的大小，代码如下：
public class primaryscreen
{
#region win32 api
[dllimport("user32.dll")]
static extern intptr getdc(intptr ptr);
[dllimport("gdi32.dll")]
static extern int getdevicecaps(
intptr hdc, // handle to dc
int nindex // index of capability
);
[dllimport("user32.dll", entrypoint = "releasedc")]
static extern intptr releasedc(intptr hwnd, intptr hdc);
#endregion
#region devicecaps常量
const int horzres = 8;
const int vertres = 10;
const int logpixelsx = 88;
const int logpixelsy = 90;
const int desktopvertres = 117;
const int desktophorzres = 118;
#endregion
#region 属性
/// <summary>
/// 获取屏幕分辨率当前物理大小
/// </summary>
public static size workingarea
{
get
{
intptr hdc = getdc(intptr.zero);
size size = new size();
size.width = getdevicecaps(hdc, horzres);
size.height = getdevicecaps(hdc, vertres);
releasedc(intptr.zero, hdc);
return size;
}
}
/// <summary>
/// 当前系统dpi_x 大小 一般为96
/// </summary>
public static int dpix
{
get
{
intptr hdc = getdc(intptr.zero);
int dpix = getdevicecaps(hdc, logpixelsx);
releasedc(intptr.zero, hdc);
return dpix;
}
}
/// <summary>
/// 当前系统dpi_y 大小 一般为96
/// </summary>
public static int dpiy
{
get
{
intptr hdc = getdc(intptr.zero);
int dpix = getdevicecaps(hdc, logpixelsy);
releasedc(intptr.zero, hdc);
return dpix;
}
}
/// <summary>
/// 获取真实设置的桌面分辨率大小
/// </summary>
public static size desktop
{
get
{
intptr hdc = getdc(intptr.zero);
size size = new size();
size.width = getdevicecaps(hdc, desktophorzres);
size.height = getdevicecaps(hdc, desktopvertres);
releasedc(intptr.zero, hdc);
return size;
}
}
/// <summary>
/// 获取宽度缩放百分比
/// </summary>
public static float scalex
{
get
{
intptr hdc = getdc(intptr.zero);
int t = getdevicecaps(hdc, desktophorzres);
int d = getdevicecaps(hdc, horzres);
float scalex = (float)getdevicecaps(hdc, desktophorzres) / (float)getdevicecaps(hdc, horzres);
releasedc(intptr.zero, hdc);
return scalex;
}
}
/// <summary>
/// 获取高度缩放百分比
/// </summary>
public static float scaley
{
get
{
intptr hdc = getdc(intptr.zero);
float scaley = (float)(float)getdevicecaps(hdc, desktopvertres) / (float)getdevicecaps(hdc, vertres);
releasedc(intptr.zero, hdc);
return scaley;
}
}
#endregion
}
使用 primaryscreen.desktop 就可以获取桌面分辨率的大小了，有了这个大小，就可以开始全屏截图了，代码如下：
public class imagehelper
{
/// <summary>
/// 截取全屏
/// </summary>
/// <returns></returns>
public static bitmap getscreen()
{
size screensize = primaryscreen.desktop;
bitmap bmp = new bitmap(screensize.width, screensize.height);
using (graphics g = graphics.fromimage(bmp))
g.copyfromscreen(0, 0, 0, 0, new size(screensize.width, screensize.height));
return bmp;
}
/// <summary>
/// 图像明暗调整
/// </summary>
/// <param name="b">原始图</param>
/// <param name="degree">亮度[-255, 255]</param>
public static void lighten(bitmap b, int degree)
{
if (b == null)
{
//return null;
return;
}
if (degree < -255) degree = -255;
if (degree > 255) degree = 255;
try
{
int width = b.width;
int height = b.height;
int pix = 0;
bitmapdata data = b.lockbits(new rectangle(0, 0, width, height), imagelockmode.readwrite, pixelformat.format24bpprgb);
unsafe
{
byte* p = (byte*)data.scan0;
int offset = data.stride - width * 3;
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
// 处理指定位置像素的亮度
for (int i = 0; i < 3; i++)
{
pix = p[i] + degree;
if (degree < 0) p[i] = (byte)math.max(0, pix);
if (degree > 0) p[i] = (byte)math.min(255, pix);
} // i
p += 3;
} // x
p += offset;
} // y
}
b.unlockbits(data);
//return b;
}
catch
{
//return null;
}
} // end of lighten
}
调用 imagehelper.getscreen() 即可以获取全屏截图
再然后，为了实现区域截图，我们需要把全屏截图放到一个窗体里面进行裁剪，弹出裁剪窗体的代码如下：
private void button1_click(object sender, eventargs e)
{
this.opacity = 0; //先隐藏自己
bitmap bitmap = imagehelper.getscreen(); //截取全屏
getscreenform frm = new getscreenform(bitmap); //准备区域截图
frm.showdialog(); //弹出区域截图界面
this.opacity = 1; //显示自己
}
区域截图的代码有点多，无非就是鼠标按下、移动、松开的相关处理，以对全屏截图进行裁剪处理，代码如下：
public partial class getscreenform : form
{
/// <summary>
/// 亮图（原图）
/// </summary>
public bitmap bitmap { get; set; }
/// <summary>
/// 暗图
/// </summary>
public bitmap bitmap2 { get; set; }
/// <summary>
/// 屏幕的宽
/// </summary>
public int w { get; set; }
/// <summary>
/// 屏幕的高
/// </summary>
public int h { get; set; }
/// <summary>
/// 适用于高dpi的宽度
/// </summary>
public int w2 { get; set; }
/// <summary>
/// 适用于高dpi的高度
/// </summary>
public int h2 { get; set; }
graphics g;
bitmap cache;
graphics gmain;
/// <summary>
/// 构造方法
/// </summary>
public getscreenform(bitmap bitmap)
{
//亮图 （也就是原图）
this.bitmap = bitmap;
this.w = bitmap.width;
this.h = bitmap.height;
//暗图
this.bitmap2 = new bitmap(bitmap.width, bitmap.height);
using (graphics g = graphics.fromimage(bitmap2))
g.drawimage(bitmap, 0, 0);
imagehelper.lighten(bitmap2, -100);
//求出适用于高dpi的宽和高
w2 = (int)(bitmap2.width * primaryscreen.scalex);
h2 = (int)(bitmap2.height * primaryscreen.scaley);
//初始化
initializecomponent();
this.width = (int)(this.w / primaryscreen.scalex);
this.height = (int)(this.h / primaryscreen.scaley);
//绘图相关
cache = new bitmap(this.w, this.h);
gmain = this.creategraphics();
g = graphics.fromimage(cache);
}
/// <summary>
/// 双击关闭
/// </summary>
protected override void ondoubleclick(eventargs e)
{
//获取截图
if (sx > int.minvalue && sy > int.minvalue)
{
//获取区域
int x1 = sx, x2 = sx + sw;
if (x1 > x2) { x2 = x1 + x2; x1 = x2 - x1; x2 = x2 - x1; };
int y1 = sy, y2 = sy + sh;
if (y1 > y2) { y2 = y1 + y2; y1 = y2 - y1; y2 = y2 - y1; };
//截图
bitmap bmp = new bitmap(x2 - x1, y2 - y1);
graphics g6 = graphics.fromimage(bmp);
g6.drawimage(bitmap,
new rectangle(0, 0, bmp.width, bmp.height),
new rectangle((int)(x1 * primaryscreen.scalex), (int)(y1 * primaryscreen.scaley), (int)((x2 - x1) * primaryscreen.scalex), (int)((y2 - y1) * primaryscreen.scaley)),
graphicsunit.pixel);
bmp.save("x.jpg", imageformat.jpeg);
}
this.close();
}
private void getscreenform_load(object sender, eventargs e)
{
}
protected override void onshown(eventargs e)
{
drawform();
}
void drawform()
{
//画暗图
g.drawimage(bitmap2,
new rectangle(0, 0, w, h), //目标
new rectangle(0, 0, w2, h2), //源
graphicsunit.pixel);
//画亮图
if (sx > int.minvalue && sy > int.minvalue)
{
g.drawimage(bitmap,
new rectangle(sx, sy, sw, sh),
new rectangle((int)(sx * primaryscreen.scalex), (int)(sy * primaryscreen.scaley), (int)(sw * primaryscreen.scalex), (int)(sh * primaryscreen.scaley)),
graphicsunit.pixel);
//new rectangle(sx, sy, sw, sh), //目标
//new rectangle(sx, sy, sw, sh), //源
//graphicsunit.pixel);
}
//翻转
gmain.drawimage(cache, 0, 0);
}
/// <summary>
/// 选择的区域
/// </summary>
public int sx { get; set; } = int.minvalue;
public int sy { get; set; } = int.minvalue;
public int sw { get; set; }
public int sh { get; set; }
/// <summary>
/// 工作类型 0未工作 1画框 2移框
/// </summary>
public int worktype { get; set; }
/// <summary>
/// 移动的起点
/// </summary>
public int movex { get; set; }
public int movey { get; set; }
protected override void onmousedown(mouseeventargs e)
{
//判断是不是点击在框里
bool inside = false;
if (sx > int.minvalue && sy > int.minvalue)
{
int x1 = sx, x2 = sx + sw;
if (x1 > x2) { x2 = x1 + x2; x1 = x2 - x1; x2 = x2 - x1; };
int y1 = sy, y2 = sy + sh;
if (y1 > y2) { y2 = y1 + y2; y1 = y2 - y1; y2 = y2 - y1; };
if (e.x > x1 && e.x < x2
&& e.y > y1 && e.y < y2)
{
inside = true;
}
}
if (inside)
{
//在框里，则进行移框
this.movex = e.x;
this.movey = e.y;
this.worktype = 2;
drawform();
}
else
{
//在框外，则重新画框
this.sx = e.x;
this.sy = e.y;
this.sw = 0;
this.sh = 0;
this.worktype = 1;
drawform();
}
}
protected override void onmousemove(mouseeventargs e)
{
if (e.button == mousebuttons.left)
{
if (this.worktype == 1)
{
//画框
this.sw = e.x - this.sx;
this.sh = e.y - this.sy;
}
else
{
//移框
this.sx += e.x - this.movex;
this.sy += e.y - this.movey;
this.movex = e.x;
this.movey = e.y;
}
drawform();
}
}
protected override void onmouseup(mouseeventargs e)
{
if (this.worktype == 1)
{
this.sw = e.x - this.sx;
this.sh = e.y - this.sy;
}
this.worktype = 0;
drawform();
}
}
提供源代码给大家玩玩，点这里下载源代码。
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