/// <summary>
/// Resize the image to the specified width and height.
/// 指定长宽裁剪
/// 按模版比例最大范围的裁剪图片并缩放至模版尺寸
/// </summary>
/// <param name="image">The image to resize.</param>
/// <param name="width">The width to resize to.</param>
/// <param name="height">The height to resize to.</param>
/// <returns>The resized image.</returns>
public static System.Drawing.Bitmap CustomImage(System.Drawing.Image initImage, int maxWidth, int maxHeight)
{
//a holder for the result
Bitmap result = new Bitmap(maxWidth, maxHeight);
//set the resolutions the same to avoid cropping due to resolution differences
result.SetResolution(initImage.HorizontalResolution, initImage.VerticalResolution);
//use a graphics object to draw the resized image into the bitmap
using (Graphics graphics = Graphics.FromImage(result))
{
//模版的宽高比例
double templateRate = (double)maxWidth / maxHeight;
//原图片的宽高比例
double initRate = (double)initImage.Width / initImage.Height;
//原图与模版比例相等，直接缩放
if (templateRate == initRate)
{
//按模版大小生成最终图片
graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
graphics.Clear(Color.White);
graphics.DrawImage(initImage, new System.Drawing.Rectangle(0, 0, maxWidth, maxHeight), new System.Drawing.Rectangle(0, 0, initImage.Width, initImage.Height), System.Drawing.GraphicsUnit.Pixel);
}
//原图与模版比例不等，裁剪后缩放
else
{
//裁剪对象
System.Drawing.Image pickedImage = null;
System.Drawing.Graphics pickedG = null;
//定位
Rectangle fromR = new Rectangle(0, 0, 0, 0); //原图裁剪定位
Rectangle toR = new Rectangle(0, 0, 0, 0); //目标定位
//宽为标准进行裁剪
if (templateRate > initRate)
{
//裁剪对象实例化
pickedImage = new System.Drawing.Bitmap(initImage.Width, (int)System.Math.Floor(initImage.Width / templateRate));
pickedG = System.Drawing.Graphics.FromImage(pickedImage);
//裁剪源定位
fromR.X = 0;
fromR.Y = (int)System.Math.Floor((initImage.Height - initImage.Width / templateRate) / 2);
fromR.Width = initImage.Width;
fromR.Height = (int)System.Math.Floor(initImage.Width / templateRate);
//裁剪目标定位
toR.X = 0;
toR.Y = 0;
toR.Width = initImage.Width;
toR.Height = (int)System.Math.Floor(initImage.Width / templateRate);
}
//高为标准进行裁剪
else
{
pickedImage = new System.Drawing.Bitmap((int)System.Math.Floor(initImage.Height * templateRate), initImage.Height);
pickedG = System.Drawing.Graphics.FromImage(pickedImage);
fromR.X = (int)System.Math.Floor((initImage.Width - initImage.Height * templateRate) / 2);
fromR.Y = 0;
fromR.Width = (int)System.Math.Floor(initImage.Height * templateRate);
fromR.Height = initImage.Height;
toR.X = 0;
toR.Y = 0;
toR.Width = (int)System.Math.Floor(initImage.Height * templateRate);
toR.Height = initImage.Height;
}
//设置质量
pickedG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
pickedG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//裁剪
pickedG.DrawImage(initImage, toR, fromR, System.Drawing.GraphicsUnit.Pixel);
//按模版大小生成最终图片
graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
graphics.Clear(Color.Transparent);
graphics.DrawImage(pickedImage, new System.Drawing.Rectangle(0, 0, maxWidth, maxHeight), new System.Drawing.Rectangle(0, 0, pickedImage.Width, pickedImage.Height), System.Drawing.GraphicsUnit.Pixel);
//释放资源
pickedImage.Dispose();
pickedG.Dispose();
}
}
//return the resulting bitmap
return(result);
}
/// <summary>
/// Resize the image to the specified width and height.
/// 图片等比缩放
/// </summary>
/// <param name="image">The image to resize.</param>
/// <param name="width">The width to resize to.</param>
/// <param name="height">The height to resize to.</param>
/// <returns>The resized image.</returns>
public static System.Drawing.Bitmap ZoomAutoImage(System.Drawing.Image initImage, int maxWidth, int maxHeight)
{
//a holder for the result
Bitmap result = new Bitmap(maxWidth, maxHeight);
//set the resolutions the same to avoid cropping due to resolution differences
result.SetResolution(initImage.HorizontalResolution, initImage.VerticalResolution);
//use a graphics object to draw the resized image into the bitmap
using (Graphics graphics = Graphics.FromImage(result))
{
//模版的宽高比例
double templateRate = (double)maxWidth / maxHeight;
//原图片的宽高比例
double initRate = (double)initImage.Width / initImage.Height;
//原图与模版比例相等，直接缩放
if (templateRate == initRate)
{
//按模版大小生成最终图片
graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
graphics.Clear(Color.White);
graphics.DrawImage(initImage, new System.Drawing.Rectangle(0, 0, maxWidth, maxHeight), new System.Drawing.Rectangle(0, 0, initImage.Width, initImage.Height), System.Drawing.GraphicsUnit.Pixel);
}
//原图与模版比例不等，裁剪后缩放
else
{
int x, y, w, h;
int twidth = maxWidth;
int height = maxHeight;
if (initImage.Width > twidth && initImage.Height > height)
{
w = twidth;
h = twidth * initImage.Height / initImage.Width;
if (h > height)
{
h = height;
w = height * initImage.Width / initImage.Height;
x = (twidth - w) / 2;
y = 0;
}
else
{
x = 0;
y = (height - h) / 2;
}
}
else if (initImage.Width > twidth)
{
w = twidth;
h = twidth * initImage.Height / initImage.Width;
x = 0;
y = (height - h) / 2;
}
else if (initImage.Height > height)
{
h = height;
w = height * initImage.Width / initImage.Height;
x = (twidth - w) / 2;
y = 0;
}
else
{
w = initImage.Width;
h = initImage.Height;
x = (twidth - w) / 2;
y = (height - h) / 2;
}
//按模版大小生成最终图片
graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
graphics.Clear(Color.White);
graphics.DrawImage(initImage, new Rectangle(x, y, w, h), 0, 0, initImage.Width, initImage.Height, GraphicsUnit.Pixel);
}
}
//return the resulting bitmap
return(result);
}