C# GDI

绘制实心矩形

using (Graphics gp = Graphics.FromImage(bmBlank))
{
//...
int y = (int)currentPoint.Y - 5;
Rectangle rec = new Rectangle(87, y, 40, 30);//画一个白块,即起到擦拭的效果
gp.FillRectangle(Brushes.White, rec);

string backImage = GetMaterialPath(param, this.reportType) + "image_blank_1.png";
using (Image im = Image.FromFile(backImage))
{
using (Bitmap bmBlank = new Bitmap(230, 60, Graphics.FromImage(im)))
{
using (Graphics gp = Graphics.FromImage(bmBlank))
{
gp.DrawImage(im, new Point(0, 0));
int width = (int)GetWidth_1(teamScore);
Rectangle rec = new Rectangle((int)baseX, (int)baseY, width, 29);
gp.FillRectangle(Brushes.Gold, rec);
}
ImageOperation.SaveImage(bmBlank, saveImgFilePath, 100000);
}
}

//自定义工具类ImageOperation
public static void SaveImage(Bitmap myBitmap,string fileName, int quality)
{

System.Drawing.Imaging.EncoderParameters myEncoderParameters =
new System.Drawing.Imaging.EncoderParameters(1);

System.Drawing.Imaging.EncoderParameter myEncoderParameter =
new System.Drawing.Imaging.EncoderParameter(
System.Drawing.Imaging.Encoder.Quality, quality);

myEncoderParameters.Param[0] = myEncoderParameter;

System.Drawing.Imaging.ImageCodecInfo myImageCodecInfo;
myImageCodecInfo = GetEncoderInfo("image/jpeg");

string ext = myImageCodecInfo.FilenameExtension.Split(';')[0];
ext = System.IO.Path.GetExtension(ext).ToLower();

string saveName = System.IO.Path.ChangeExtension(fileName, ext);

//保存
myBitmap.Save(saveName, myImageCodecInfo, myEncoderParameters);
}

using (FileStream fs = new FileStream(saveImgFilePath, FileMode.Create))
{
ImageCodecInfo imageCodeInfo = ImageOperation.GetEncoderInfo("image/jpeg");
System.Drawing.Imaging.Encoder myEncoder = System.Drawing.Imaging.Encoder.Quality;
EncoderParameters myEncoderParameters = new EncoderParameters(1);
myEncoderParameters.Param[0] = new EncoderParameter(myEncoder, 99L);
bmBlank.Save(fs, imageCodeInfo, myEncoderParameters);
}

原生自定义背景色

Bitmap bmBlank = new Bitmap(width, height);
using (Graphics gp = Graphics.FromImage(bmBlank))
{
//清空画布并以白色背景色填充
gp.Clear(Color.White);
for (int i = 0; i < imagePaths.Length; i++)
{
//加载一个图片
string imagePath = imagePaths[i];
//封装成Bitmap
Bitmap bm = new Bitmap(Image.FromFile(imagePath));
//切割此Bitmap为了等比例缩放
Bitmap newbm = ImageOperation.Cut(bm, 200, 0, 800, 800);
//查找所绘制每张图的新坐标
int x = xValue[i];
int y = yValue[i];
gp.DrawImage(newbm, x, y, 400, 400);
bm.Dispose();
}
gp.Dispose();
//保存为图片...
}