C#，图片分层（Layer Bitmap）绘制，反色、高斯模糊及凹凸贴图等处理的高速算法与源程序

1 图像反色Invert

对图像处理的过程中会遇到一些场景需要将图片反色，反色就是取像素的互补色，比如当前像素是0X00FFFF，对其取反色就是0XFFFFFF – 0X00FFFF = 0XFF0000，依次对图像中的每个像素这样做，最后得到的就是原始2 图像的反色。

2 高斯模糊（Gauss Blur）算法

高斯模糊（英语：Gaussian Blur），也叫高斯平滑，是在Adobe Photoshop、GIMP以及Paint.NET等图像处理软件中广泛使用的处理效果，通常用它来减少图像噪声以及降低细节层次。这种模糊技术生成的图像，其视觉效果就像是经过一个毛玻璃在观察图像，这与镜头焦外成像效果散景以及普通照明阴影中的效果都明显不同。高斯平滑也用于计算机视觉算法中的预先处理阶段，以增强图像在不同比例大小下的图像效果（参见尺度空间表示以及尺度空间实现）。从数学的角度来看，图像的高斯模糊过程就是图像与正态分布做卷积。由于正态分布又叫作高斯分布，所以这项技术就叫作高斯模糊。图像与圆形方框模糊做卷积将会生成更加精确的焦外成像效果。由于高斯函数的傅立叶变换是另外一个高斯函数，所以高斯模糊对于图像来说就是一个低通滤波器。

3 凹凸贴图bump map

所有物体表面多少都会有一点凹凸的质感，但建模时如果需要再现这些质感，一个一个建或雕刻就太麻烦了。 bump maps这个参数就是利用光线和阴影的控制去制造凹凸质感的假象，但毕竟是利用光线，所以如果是特写镜头或特定角度(平面)还是会漏馅。

参考：

C#，图片像素（Bitmap Pixel）的读取与绘制的快速方法与源程序https://blog.csdn.net/beijinghorn/article/details/125253281

4 源代码 Layer.cs：

using System;
using System.Text;
using System.Collections;
using System.Windows.Forms;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;class Layer : ICloneable
{internal FastBitmap _bitmap;private FastBitmap _mask;public Double _opacity;private Int32 _offsetx, _offsety;public Layer(Int32 width, Int32 height){_bitmap = new FastBitmap(width, height, PixelFormat.Format32bppArgb);Clear(Color.Transparent);_opacity = 1.0;}public Double Opacity{get { return _opacity; }set	{ _opacity = value; }}public FastBitmap Bitmap{get { return _bitmap; }}public FastBitmap Mask{get { return _mask; }set { _mask = value; }}public Int32 OffsetX{get { return _offsetx; }set { _offsetx = value; }}public Int32 OffsetY{get { return _offsety; }set { _offsety = value; }}public Object Clone(){Layer clone = new Layer(_bitmap.Width, _bitmap.Height);clone._bitmap = (FastBitmap)_bitmap.Clone();return clone;}public void Clear(Color c){_bitmap.Lock();for (Int32 y = 0; y < _bitmap.Height; y++)for (Int32 x = 0; x < _bitmap.Width; x++)_bitmap.SetPixel(x, y, c);_bitmap.Unlock();}public void DrawText(Int32 x, Int32 y, String text, Font font,Brush brush){Graphics g = Graphics.FromImage(_bitmap._bitmap);g.DrawString(text, font, brush, x, y, StringFormat.GenericTypographic);g.Dispose();}public void FillRectangle(Int32 x, Int32 y, Int32 width,Int32 height, Brush brush){Graphics g = Graphics.FromImage(_bitmap._bitmap);g.FillRectangle(brush, x, y, width, height);g.Dispose();}public Color GetPixel(Int32 x, Int32 y){return _bitmap.GetPixel(x, y);}public void Invert(){_bitmap.Lock();for (Int32 y = 0; y < _bitmap.Height; y++) {for (Int32 x = 0; x < _bitmap.Width; x++) {Color c = _bitmap.GetPixel(x, y);_bitmap.SetPixel(x, y, Color.FromArgb(c.A,255 - c.R, 255 - c.G, 255 - c.B));}}_bitmap.Unlock();}private Single Gauss(Single x, Single middle, Single width){if (width == 0)return 1F;Double t = - (1.0 / width) * ((middle - x) * (middle - x));return (Single)Math.Pow(Math.E, t);}public void Blur(Int32 horz, Int32 vert){Single weightsum;Single[] weights;FastBitmap t = (FastBitmap)_bitmap.Clone();_bitmap.Lock();t.Lock();weights = new Single[horz * 2 + 1];for (Int32 i = 0; i < horz * 2 + 1; i++) {Single y = Gauss(-horz + i, 0, horz);weights[i] = y;}for (Int32 row = 0; row < _bitmap.Height; row++) {for (Int32 col = 0; col < _bitmap.Width; col++) {Double r = 0;Double g = 0;Double b = 0;weightsum = 0;for (Int32 i = 0; i < horz * 2 + 1; i++) {Int32 x = col - horz + i;if (x < 0) {i += -x;x = 0;}if (x > _bitmap.Width - 1)break;Color c = _bitmap.GetPixel(x, row);r += c.R * weights[i];g += c.G * weights[i];b += c.B * weights[i];weightsum += weights[i];}r /= weightsum;g /= weightsum;b /= weightsum;Byte br = (Byte)Math.Round(r);Byte bg = (Byte)Math.Round(g);Byte bb = (Byte)Math.Round(b);if (br > 255) br = 255;if (bg > 255) bg = 255;if (bb > 255) bb = 255;t.SetPixel(col, row, Color.FromArgb(br, bg, bb));}}weights = new Single[vert * 2 + 1];for (Int32 i = 0; i < vert * 2 + 1; i++) {Single y = Gauss(-vert + i, 0, vert);weights[i] = y;}for (Int32 col = 0; col < _bitmap.Width; col++) {for (Int32 row = 0; row < _bitmap.Height; row++) {Double r = 0;Double g = 0;Double b = 0;weightsum = 0;for (Int32 i = 0; i < vert * 2 + 1; i++) {Int32 y = row - vert + i;if (y < 0) {i += -y;y = 0;}if (y > _bitmap.Height - 1)break;Color c = t.GetPixel(col, y);r += c.R * weights[i];g += c.G * weights[i];b += c.B * weights[i];weightsum += weights[i];}r /= weightsum;g /= weightsum;b /= weightsum;Byte br = (Byte)Math.Round(r);Byte bg = (Byte)Math.Round(g);Byte bb = (Byte)Math.Round(b);if (br > 255) br = 255;if (bg > 255) bg = 255;if (bb > 255) bb = 255;_bitmap.SetPixel(col, row, Color.FromArgb(br, bg, bb));}}t.Dispose();_bitmap.Unlock();}private Byte GetBumpMapPixel(FastBitmap bmp, Int32 x, Int32 y){if (x < 0)x = 0;if (x > _bitmap.Width - 1)x = _bitmap.Width - 1;if (y < 0)y = 0;if (y > _bitmap.Height - 1)y = _bitmap.Height - 1;return bmp.GetIntensity(x, y);}public void BumpMap(Layer bumpmap, Int32 azimuth, Int32 elevation,Int32 bevelwidth, Boolean lightzalways1){bumpmap._bitmap.Lock();_bitmap.Lock();for (Int32 row = 0; row < _bitmap.Height; row++) {for (Int32 col = 0; col < _bitmap.Width; col++) {Byte[] x = new Byte[6];x[0] = GetBumpMapPixel(bumpmap._bitmap, col - 1, row - 1);x[1] = GetBumpMapPixel(bumpmap._bitmap, col - 1, row - 0);x[2] = GetBumpMapPixel(bumpmap._bitmap, col - 1, row + 1);x[3] = GetBumpMapPixel(bumpmap._bitmap, col + 1, row - 1);x[4] = GetBumpMapPixel(bumpmap._bitmap, col + 1, row - 0);x[5] = GetBumpMapPixel(bumpmap._bitmap, col + 1, row + 1);Single normal_x = x[0] + x[1] + x[2] - x[3] - x[4] - x[5];x[0] = GetBumpMapPixel(bumpmap._bitmap, col - 1, row + 1);x[1] = GetBumpMapPixel(bumpmap._bitmap, col - 0, row + 1);x[2] = GetBumpMapPixel(bumpmap._bitmap, col + 1, row + 1);x[3] = GetBumpMapPixel(bumpmap._bitmap, col - 1, row - 1);x[4] = GetBumpMapPixel(bumpmap._bitmap, col - 0, row - 1);x[5] = GetBumpMapPixel(bumpmap._bitmap, col + 1, row - 1);Single normal_y = x[0] + x[1] + x[2] - x[3] - x[4] - x[5];Single normal_z = (6F * 255F) / bevelwidth;Single length = (Single)Math.Sqrt(normal_x * normal_x +normal_y * normal_y +normal_z * normal_z);if (length != 0) {normal_x /= length;normal_y /= length;normal_z /= length;}Double azimuth_rad = azimuth / 180.0 * Math.PI;Double elevation_rad = elevation / 180.0 * Math.PI;Single light_x = (Single)(Math.Cos(azimuth_rad) * Math.Cos(elevation_rad));Single light_y = (Single)(Math.Sin(azimuth_rad) * Math.Cos(elevation_rad));Single light_z = 1F;if (!lightzalways1)light_z = (Single)Math.Sin(elevation_rad);Single cos_light_normal = 0;cos_light_normal += normal_x * light_x;cos_light_normal += normal_y * light_y;cos_light_normal += normal_z * light_z;Color c = _bitmap.GetPixel(col, row);Single r = c.R;Single g = c.G;Single b = c.B;r *= cos_light_normal;g *= cos_light_normal;b *= cos_light_normal;Byte red = (Byte)Math.Min(Math.Round(r), 255);Byte green = (Byte)Math.Min(Math.Round(g), 255);Byte blue = (Byte)Math.Min(Math.Round(b), 255);_bitmap.SetPixel(col, row, Color.FromArgb(red, green, blue));}}_bitmap.Unlock();bumpmap._bitmap.Unlock();}
}

5 源代码 Layers.cs：

using System;
using System.Text;
using System.Collections;
using System.Windows.Forms;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;class Layers
{LayeredImage _image;ArrayList _layers = new ArrayList();public Layers(LayeredImage image){_image = image;}public Int32 Count{get { return _layers.Count; }}public Layer Add(){Layer layer = new Layer(_image.Width, _image.Height);_layers.Add(layer);return layer;}public Layer Copy(Layer layer){Layer copy = (Layer)layer.Clone();_layers.Add(copy);return copy;}public Layer this[Int32 i]{get { return (Layer)_layers[i]; }}
}

6 源代码 LayeredImage.cs：

using System;
using System.Text;
using System.Collections;
using System.Windows.Forms;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;class LayeredImage
{Int32 _width, _height;Bitmap _checkerboard;Layers _layers;public LayeredImage(Int32 width, Int32 height){_width = width;_height = height;_layers = new Layers(this);_checkerboard = new Bitmap(32, 32, PixelFormat.Format24bppRgb);Color darkgray = Color.FromArgb(102,102,102);Color lightgray = Color.FromArgb(153,153,153);for (Int32 i = 0; i < 32; i++) {for (Int32 j = 0; j < 32; j++) {if ((i < 16 && j < 16) || (i >= 16 && j >= 16))_checkerboard.SetPixel(j, i, lightgray);else_checkerboard.SetPixel(j, i, darkgray);}}Layer bglayer = _layers.Add();Graphics g = Graphics.FromImage(bglayer._bitmap._bitmap);TextureBrush brush = new TextureBrush(_checkerboard);g.FillRectangle(brush, 0, 0, _width, _height);brush.Dispose();g.Dispose();}public Int32 Width{get { return _width; }}public Int32 Height{get { return _height; }}public Layers Layers{get { return _layers; }}internal FastBitmap Flatten(){FastBitmap final = new FastBitmap(_width, _height,PixelFormat.Format24bppRgb);final.Lock();for (Int32 i = 0; i < _layers.Count; i++) {Layer l = _layers[i];l._bitmap.Lock();if (l.Mask != null)l.Mask.Lock();}for (Int32 y = 0; y < _height; y++) {for (Int32 x = 0; x < _width; x++) {Color c0 = _layers[0]._bitmap.GetPixel(x, y);for (Int32 i = 1; i < _layers.Count; i++) {Layer layer = _layers[i];Color c1 = Color.Transparent;if (x >= layer.OffsetX &&x <= layer.OffsetX + layer._bitmap.Width - 1 &&y >= layer.OffsetY &&y <= layer.OffsetY + layer._bitmap.Height - 1) {c1 = layer._bitmap.GetPixel(x - layer.OffsetX,y - layer.OffsetY);}if (c1.A == 255 && layer.Opacity == 1.0 &&layer.Mask == null) {c0 = c1;} else {Double tr, tg, tb, a;a = c1.A / 255.0 * layer.Opacity;if (layer.Mask != null) {a *= layer.Mask.GetIntensity(x, y) / 255.0;}tr = c1.R * a + c0.R * (1.0 - a);tg = c1.G * a + c0.G * (1.0 - a);tb = c1.B * a + c0.B * (1.0 - a);tr = Math.Round(tr);tg = Math.Round(tg);tb = Math.Round(tb);tr = Math.Min(tr, 255);tg = Math.Min(tg, 255);tb = Math.Min(tb, 255);c0 = Color.FromArgb((Byte)tr, (Byte)tg, (Byte)tb);}}final.SetPixel(x, y, c0);}}for (Int32 i = 0; i < _layers.Count; i++) {Layer l = _layers[i];l._bitmap.Unlock();if (l.Mask != null)l.Mask.Unlock();}final.Unlock();return final;}
}