c to generate image thumbnail class of 2 implementation ideas
- 2020-06-12 08:49:37
- OfStack
1 kind
Key method Graphics. See DrawImage ms - help: / / MS NETFrameworkSDKv1. 1. CHS cpref/html/frlrfsystemdrawinggraphicsclassdrawimagetopic11 htm
2 kinds of
4 overloaded methods, some return Image object directly, some generate thumbnails, and save to the specified directory!
/**//// <summary>
/// Generate thumbnails
/// </summary>
/// <param name="originalImagePath"> Source map path (physical path) </param>
/// <param name="thumbnailPath"> Thumbnail path (physical path) </param>
/// <param name="width"> Thumbnail width </param>
/// <param name="height"> Thumbnail height </param>
/// <param name="mode"> How to generate thumbnails </param>
public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
{
Image originalImage = Image.FromFile(originalImagePath);
int towidth = width;
int toheight = height;
int x = 0;
int y = 0;
int ow = originalImage.Width;
int oh = originalImage.Height;
switch (mode)
{
case "HW":// Specify height and width scaling (possible distortion)
break;
case "W":// Specify width and height to scale
toheight = originalImage.Height * width/originalImage.Width;
break;
case "H":// Specify height and width in proportion
towidth = originalImage.Width * height/originalImage.Height;
break;
case "Cut":// Specified height and width cut (without deformation)
if((double)originalImage.Width/(double)originalImage.Height > (double)towidth/(double)toheight)
{
oh = originalImage.Height;
ow = originalImage.Height*towidth/toheight;
y = 0;
x = (originalImage.Width - ow)/2;
}
else
{
ow = originalImage.Width;
oh = originalImage.Width*height/towidth;
x = 0;
y = (originalImage.Height - oh)/2;
}
break;
default :
break;
}
// new 1 a bmp The picture
Image bitmap = new System.Drawing.Bitmap(towidth,toheight);
// new 1 A drawing board
Graphics g = System.Drawing.Graphics.FromImage(bitmap);
// Set up a high quality interpolation
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
// Set high quality , Low speed presents smoothness
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
// Empty the canvas and fill it with a transparent background color
g.Clear(Color.Transparent);
// Draws the specified part of the original image at the specified location and at the specified size
g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight),
new Rectangle(x, y, ow,oh),
GraphicsUnit.Pixel);
try
{
// In order to jpg Format to save thumbnails
bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
}
catch(System.Exception e)
{
throw e;
}
finally
{
originalImage.Dispose();
bitmap.Dispose();
g.Dispose();
}
}
Key method Graphics. See DrawImage ms - help: / / MS NETFrameworkSDKv1. 1. CHS cpref/html/frlrfsystemdrawinggraphicsclassdrawimagetopic11 htm
2 kinds of
4 overloaded methods, some return Image object directly, some generate thumbnails, and save to the specified directory!
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
/// <summary>
/// Picture processing class
/// 1 , generate thumbnail images or change the size and quality of images to scale
/// 2 , put the generated thumbnails in the specified directory
/// </summary>
public class ImageClass
{
public Image ResourceImage;
private int ImageWidth;
private int ImageHeight;
public string ErrMessage;
/// <summary>
/// Class constructor
/// </summary>
/// <param name="ImageFileName"> The full path name of the image file </param>
public ImageClass(string ImageFileName)
{
ResourceImage=Image.FromFile(ImageFileName);
ErrMessage="";
}
public bool ThumbnailCallback()
{
return false;
}
/// <summary>
/// Generate thumbnail overload methods 1 , which returns the thumbnail Image object
/// </summary>
/// <param name="Width"> The width of the thumbnail </param>
/// <param name="Height"> Thumbnail height </param>
/// <returns> The thumbnail Image object </returns>
public Image GetReducedImage(int Width,int Height)
{
try
{
Image ReducedImage;
Image.GetThumbnailImageAbort callb=new Image.GetThumbnailImageAbort(ThumbnailCallback);
ReducedImage=ResourceImage.GetThumbnailImage(Width,Height,callb,IntPtr.Zero);
return ReducedImage;
}
catch(Exception e)
{
ErrMessage=e.Message;
return null;
}
}
/// <summary>
/// Generate thumbnail overload methods 2 , saves the thumbnail file to the specified path
/// </summary>
/// <param name="Width"> The width of the thumbnail </param>
/// <param name="Height"> Thumbnail height </param>
/// <param name="targetFilePath"> Full filename saved by thumbnail, ( With path ) , parameter format: D:Images ilename.jpg</param>
/// <returns> Successfully returns true Otherwise return false</returns>
public bool GetReducedImage(int Width,int Height,string targetFilePath)
{
try
{
Image ReducedImage;
Image.GetThumbnailImageAbort callb=new Image.GetThumbnailImageAbort(ThumbnailCallback);
ReducedImage=ResourceImage.GetThumbnailImage(Width,Height,callb,IntPtr.Zero);
ReducedImage.Save(@targetFilePath,ImageFormat.Jpeg);
ReducedImage.Dispose();
return true;
}
catch(Exception e)
{
ErrMessage=e.Message;
return false;
}
}
/// <summary>
/// Generate thumbnail overload methods 3 , which returns the thumbnail Image object
/// </summary>
/// <param name="Percent"> Percentage width of thumbnails Percent is needed 80 , just fill in the 0.8</param>
/// <returns> The thumbnail Image object </returns>
public Image GetReducedImage(double Percent)
{
try
{
Image ReducedImage;
Image.GetThumbnailImageAbort callb=new Image.GetThumbnailImageAbort(ThumbnailCallback);
ImageWidth=Convert.ToInt32(ResourceImage.Width*Percent);
ImageHeight=Convert.ToInt32(ResourceImage.Width*Percent);
ReducedImage=ResourceImage.GetThumbnailImage(ImageWidth,ImageHeight,callb,IntPtr.Zero);
return ReducedImage;
}
catch(Exception e)
{
ErrMessage=e.Message;
return null;
}
}
/// <summary>
/// Generate thumbnail overload methods 4 , which returns the thumbnail Image object
/// </summary>
/// <param name="Percent"> Percentage width of thumbnails Percent is needed 80 , just fill in the 0.8</param>
/// <param name="targetFilePath"> Full filename saved by thumbnail, ( With path ) , parameter format: D:Images ilename.jpg</param>
/// <returns> Successfully returns true, Otherwise returns false</returns>
public bool GetReducedImage(double Percent,string targetFilePath)
{
try
{
Image ReducedImage;
Image.GetThumbnailImageAbort callb=new Image.GetThumbnailImageAbort(ThumbnailCallback);
ImageWidth=Convert.ToInt32(ResourceImage.Width*Percent);
ImageHeight=Convert.ToInt32(ResourceImage.Width*Percent);
ReducedImage=ResourceImage.GetThumbnailImage(ImageWidth,ImageHeight,callb,IntPtr.Zero);
ReducedImage.Save(@targetFilePath,ImageFormat.Jpeg);
ReducedImage.Dispose();
return true;
}
catch(Exception e)
{
ErrMessage=e.Message;
return false;
}
}
}