【C#】图片处理（底片，黑白，锐化，柔化，浮雕，雾化）

通过GDI+对图片数据进行处理，下面列出各个效果的算法

对于读取图片的每个像素颜色的速度非常慢，这里使用LockBitmap类来对图片像素进行操作，LockBitmap类的定义看这里

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1、旋转（90度，180度，270度）

//旋转90,180,270
public Bitmap RotateImage(Bitmap bmp, int angle)
{
if (angle != 90 && angle != 180 && angle != 270)
{
return null;
}
int width = bmp.Width;
int height = bmp.Height;

if (angle == 90)
{
Bitmap newbmp = new Bitmap(height, width);
using (Graphics g = Graphics.FromImage(newbmp))
{
Point[] destinationPoints = {
new Point(height, 0), // destination for upper-left point of original
new Point(height, width),// destination for upper-right point of original
new Point(0, 0)}; // destination for lower-left point of original
g.DrawImage(bmp, destinationPoints);
}
return newbmp;
}

if (angle == 180)
{
Bitmap newbmp = new Bitmap(width, height);
using (Graphics g = Graphics.FromImage(newbmp))
{
Point[] destinationPoints = {
new Point(width, height), // destination for upper-left point of original
new Point(0, height),// destination for upper-right point of original
new Point(width, 0)}; // destination for lower-left point of original
g.DrawImage(bmp, destinationPoints);
}
return newbmp;
}

if(angle == 270)
{
Bitmap newbmp = new Bitmap(height, width);
using (Graphics g = Graphics.FromImage(newbmp))
{
Point[] destinationPoints = {
new Point(0, width), // destination for upper-left point of original
new Point(0, 0),// destination for upper-right point of original
new Point(height, width)}; // destination for lower-left point of original
g.DrawImage(bmp, destinationPoints);
}
return newbmp;
}
return null;
}

2、重设大小

//重设大小
public Bitmap ResizeImage(Bitmap bmp, Size size)
{
Bitmap newbmp = new Bitmap(size.Width, size.Height);
using (Graphics g = Graphics.FromImage(newbmp))
{
g.DrawImage(bmp, new Rectangle(Point.Empty, size));
}
return newbmp;
}

3、底片效果（反色）（255-r, 255-g, 255-b）

//底片
public Bitmap NegativeImage(Bitmap bmp)
{
int height = bmp.Height;
int width = bmp.Width;
Bitmap newbmp = new Bitmap(width, height);

LockBitmap lbmp = new LockBitmap(bmp);
LockBitmap newlbmp = new LockBitmap(newbmp);
lbmp.LockBits();
newlbmp.LockBits();

Color pixel;
for (int x = 1; x < width; x++)
{
for (int y = 1; y < height; y++)
{
int r, g, b;
pixel = lbmp.GetPixel(x, y);
r = 255 - pixel.R;
g = 255 - pixel.G;
b = 255 - pixel.B;
newlbmp.SetPixel(x, y, Color.FromArgb(r, g, b));
}
}
lbmp.UnlockBits();
newlbmp.UnlockBits();
return newbmp;
}

4、黑白效果

//黑白
public Bitmap GrayImage(Bitmap bmp, int type)
{
int height = bmp.Height;
int width = bmp.Width;
Bitmap newbmp = new Bitmap(width, height);

LockBitmap lbmp = new LockBitmap(bmp);
LockBitmap newlbmp = new LockBitmap(newbmp);
lbmp.LockBits();
newlbmp.LockBits();

Color pixel;
for (int x = 0; x < width; x++)
{
for (int y = 0; y < height; y++)
{
pixel = lbmp.GetPixel(x, y);
int r, g, b, Result = 0;
r = pixel.R;
g = pixel.G;
b = pixel.B;
switch (type)
{
case 0://平均值法
Result = ((r + g + b) / 3);
break;
case 1://最大值法
Result = r > g ? r : g;
Result = Result > b ? Result : b;
break;
case 2://加权平均值法
Result = ((int)(0.3 * r) + (int)(0.59 * g) + (int)(0.11 * b));
break;
}
newlbmp.SetPixel(x, y, Color.FromArgb(Result, Result, Result));
}
}
lbmp.UnlockBits();
newlbmp.UnlockBits();
return newbmp;
}

5、浮雕：找出附近的像素点r1，abs（r-r2+128）

//浮雕
public Bitmap EmbossmentImage(Bitmap bmp)
{
int height = bmp.Height;
int width = bmp.Width;
Bitmap newbmp = new Bitmap(width, height);

LockBitmap lbmp = new LockBitmap(bmp);
LockBitmap newlbmp = new LockBitmap(newbmp);
lbmp.LockBits();
newlbmp.LockBits();

Color pixel1, pixel2;
for (int x = 0; x < width - 1; x++)
{
for (int y = 0; y < height - 1; y++)
{
int r = 0, g = 0, b = 0;
pixel1 = lbmp.GetPixel(x, y);
pixel2 = lbmp.GetPixel(x + 1, y + 1);
r = Math.Abs(pixel1.R - pixel2.R + 128);
g = Math.Abs(pixel1.G - pixel2.G + 128);
b = Math.Abs(pixel1.B - pixel2.B + 128);
if (r > 255)
r = 255;
if (r < 0)
r = 0;
if (g > 255)
g = 255;
if (g < 0)
g = 0;
if (b > 255)
b = 255;
if (b < 0)
b = 0;
newlbmp.SetPixel(x, y, Color.FromArgb(r, g, b));
}
}
lbmp.UnlockBits();
newlbmp.UnlockBits();
return newbmp;
}

6、柔化

//柔化
public Bitmap SoftenImage(Bitmap bmp)
{
int height = bmp.Height;
int width = bmp.Width;
Bitmap newbmp = new Bitmap(width, height);

LockBitmap lbmp = new LockBitmap(bmp);
LockBitmap newlbmp = new LockBitmap(newbmp);
lbmp.LockBits();
newlbmp.LockBits();

Color pixel;
//高斯模板
int[] Gauss ={ 1, 2, 1, 2, 4, 2, 1, 2, 1 };
for (int x = 1; x < width - 1; x++)
{
for (int y = 1; y < height - 1; y++)
{
int r = 0, g = 0, b = 0;
int Index = 0;
for (int col = -1; col <= 1; col++)
{
for (int row = -1; row <= 1; row++)
{
pixel = lbmp.GetPixel(x + row, y + col);
r += pixel.R * Gauss[Index];
g += pixel.G * Gauss[Index];
b += pixel.B * Gauss[Index];
Index++;
}
}
r /= 16;
g /= 16;
b /= 16;
//处理颜色值溢出
r = r > 255 ? 255 : r;
r = r < 0 ? 0 : r;
g = g > 255 ? 255 : g;
g = g < 0 ? 0 : g;
b = b > 255 ? 255 : b;
b = b < 0 ? 0 : b;
newlbmp.SetPixel(x - 1, y - 1, Color.FromArgb(r, g, b));
}
}
lbmp.UnlockBits();
newlbmp.UnlockBits();
return newbmp;
}

7、锐化

//锐化
public Bitmap SharpenImage(Bitmap bmp)
{
int height = bmp.Height;
int width = bmp.Width;
Bitmap newbmp = new Bitmap(width, height);

LockBitmap lbmp = new LockBitmap(bmp);
LockBitmap newlbmp = new LockBitmap(newbmp);
lbmp.LockBits();
newlbmp.LockBits();

Color pixel;
//拉普拉斯模板
int[] Laplacian = { -1, -1, -1, -1, 9, -1, -1, -1, -1 };
for (int x = 1; x < width - 1; x++)
{
for (int y = 1; y < height - 1; y++)
{
int r = 0, g = 0, b = 0;
int Index = 0;
for (int col = -1; col <= 1; col++)
{
for (int row = -1; row <= 1; row++)
{
pixel = lbmp.GetPixel(x + row, y + col); r += pixel.R * Laplacian[Index];
g += pixel.G * Laplacian[Index];
b += pixel.B * Laplacian[Index];
Index++;
}
}
//处理颜色值溢出
r = r > 255 ? 255 : r;
r = r < 0 ? 0 : r;
g = g > 255 ? 255 : g;
g = g < 0 ? 0 : g;
b = b > 255 ? 255 : b;
b = b < 0 ? 0 : b;
newlbmp.SetPixel(x - 1, y - 1, Color.FromArgb(r, g, b));
}
}
lbmp.UnlockBits();
newlbmp.UnlockBits();
return newbmp;
}

8、雾化

//雾化
public Bitmap AtomizationImage(Bitmap bmp)
{
int height = bmp.Height;
int width = bmp.Width;
Bitmap newbmp = new Bitmap(width, height);

LockBitmap lbmp = new LockBitmap(bmp);
LockBitmap newlbmp = new LockBitmap(newbmp);
lbmp.LockBits();
newlbmp.LockBits();

System.Random MyRandom = new Random();
Color pixel;
for (int x = 1; x < width - 1; x++)
{
for (int y = 1; y < height - 1; y++)
{
int k = MyRandom.Next(123456);
//像素块大小
int dx = x + k % 19;
int dy = y + k % 19;
if (dx >= width)
dx = width - 1;
if (dy >= height)
dy = height - 1;
pixel = lbmp.GetPixel(dx, dy);
newlbmp.SetPixel(x, y, pixel);
}
}
lbmp.UnlockBits();
newlbmp.UnlockBits();
return newbmp;
}