C# 图形处理-缩略图,图片合并,图片写文字,图片调整
1.根据源图片生成缩略图
///
/// 根据源图片生成缩略图
///
/// 源图(大图)物理路径
/// 缩略图物理路径(生成的缩略图将保存到该物理位置)
/// 缩略图宽度
/// 缩略图高度
/// 缩略图缩放模式(取值"HW":指定高宽缩放,可能变形；取值"W":按指定宽度,高度按比例缩放；取值"H":按指定高度,宽度按比例缩放；取值"Cut":按指定高度和宽度裁剪,不变形)；取值"DB":等比缩放,以值较大的作为标准进行等比缩放
/// 即将生成缩略图的文件的扩展名(仅限：JPG、GIF、PNG、BMP)
public static void MakeThumbnail(string imgPath_old, string imgPath_new, int width, int height, string mode, string type)
{
Image img = Image.FromFile(imgPath_old);
int towidth = width; int toheight = height;
int x = 0; int y = 0; int ow = img.Width;
int oh = img.Height;
switch (mode)
{
case "HW": //指定高宽缩放（可能变形）
break;
case "W": //指定宽，高按比例
toheight = img.Height * width / img.Width;
break;
case "H": //指定高，宽按比例
towidth = img.Width * height / img.Height;
break;
case "Cut": //指定高宽裁减（不变形）
if ((double)img.Width / (double)img.Height > (double)towidth / (double)toheight)
{
oh = img.Height;
ow = img.Height * towidth / toheight;
y = 0; x = (img.Width - ow) / 2;
}
else
{
ow = img.Width;
oh = img.Width * height / towidth;
x = 0; y = (img.Height - oh) / 2;
} break;
case "DB": // 按值较大的进行等比缩放（不变形）
if ((double)img.Width / (double)towidth < (double)img.Height / (double)toheight)
{
toheight = height;
towidth = img.Width * height / img.Height;
}
else
{
towidth = width;
toheight = img.Height * width / img.Width;
} break;
default:
break;
}
//新建一个bmp图片
Image bitmap = new System.Drawing.Bitmap(towidth, toheight);
//新建一个画板
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);
//设置高质量插值法
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
//设置高质量,低速度呈现平滑程度
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//清空画布并以透明背景色填充
g.Clear(System.Drawing.Color.Transparent);
//在指定位置并且按指定大小绘制原图片的指定部分
g.DrawImage(img, new System.Drawing.Rectangle(0, 0, towidth, toheight),
new System.Drawing.Rectangle(x, y, ow, oh),
System.Drawing.GraphicsUnit.Pixel); try
{
//保存缩略图
switch (type.ToUpper())
{
case "JPG":
bitmap.Save(imgPath_new, System.Drawing.Imaging.ImageFormat.Jpeg);
break;
case "GIF":
bitmap.Save(imgPath_new, System.Drawing.Imaging.ImageFormat.Gif);
break;
case "PNG":
bitmap.Save(imgPath_new, System.Drawing.Imaging.ImageFormat.Png);
break;
case "BMP":
bitmap.Save(imgPath_new, System.Drawing.Imaging.ImageFormat.Bmp);
break;
default:
break;
}
}
catch (System.Exception e)
{
throw e;
}
finally
{
img.Dispose();
bitmap.Dispose(); g.Dispose();
}
}2.生成文字图片
///
/// 生成文字图片
///
///
///
///
public static Image CreateImage(string text, bool isBold, int fontSize)
{
int wid = 400;
int high = 200;
Font font;
if (isBold)
{
font = new Font("Arial", fontSize, FontStyle.Bold);
}
else
{
font = new Font("Arial", fontSize, FontStyle.Regular);
}
//绘笔颜色
SolidBrush brush = new SolidBrush(Color.Black);
StringFormat format = new StringFormat(StringFormatFlags.NoClip);
Bitmap image = new Bitmap(wid, high);
Graphics g = Graphics.FromImage(image);
SizeF sizef = g.MeasureString(text, font, PointF.Empty, format);//得到文本的宽高
int width = (int)(sizef.Width + 1);
int height = (int)(sizef.Height + 1);
image.Dispose();
image = new Bitmap(width, height);
g = Graphics.FromImage(image);
g.Clear(Color.White);//透明
RectangleF rect = new RectangleF(0, 0, width, height);
//绘制图片
g.DrawString(text, font, brush, rect);
//释放对象
g.Dispose();
return image;
}3.合并两个图片
///
/// 合并图片
///
///
///
/// 4.图片大小调整
///
/// Resize图片
///
/// 原始Bitmap
/// 新的宽度
/// 新的高度
/// 保留着，暂时未用
/// 处理以后的图片
public static Image ResizeImage(Image bmp, int newW, int newH, int mode)
{
try
{
Image b = new Bitmap(newW, newH);
Graphics g = Graphics.FromImage(b);
// 插值算法的质量
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
g.DrawImage(bmp, new Rectangle(0, 0, newW, newH), new Rectangle(0, 0, bmp.Width, bmp.Height),
GraphicsUnit.Pixel);
g.Dispose();
return b;
}
catch
{
return null;
}
}5.如果文章对你有帮助，记得一键三连❤