ImageMagik——开发篇（转）

//创建Image对象，  
// create a blank image canvas with 640x480 size and ‘white‘ color as background:  
 Image blank_image( Geometry(640, 480), Color(MaxRGB, MaxRGB, MaxRGB, 0));  
 // or also, by using the automatic C++ type conversions for the arguments:  
 Image blank_image("640x480", "white");  
   
 // create an image from URL  
 Image url_image("http://www.serverName.com/image.gif");  
 Image local_file_image("my_image.gif");   // here the URL points to the local filesystem  
//获取/设置属性  
// Canvas geometry  
// returns an unsigned int representing the my_image width  
unsigned int Image::columns();  
// returns an unsigned int representing the my_image heigth  
unsigned int Image::rows();  
// sets the my_image format; the format string can be "GIF", etc  
void Image::magick("png");  
// returns a string value representing the image format (e.g. “GIF”, “JPEG”, etc)  
string Image::magick();  
//读取/保存图像文件  
// Reading the contents of a disk file into an image object can be performed  
Image my_image();  // create an *empty* image using the default Image constructor  
// read a GIF image file from disk; the image format is automatically set to GIF  
my_image.read("aGIFImageFile.gif");  
// Writing an Image object to a disk file. set the "format" attribute of my_image to PNG  
my_image.magick("png");  
// write to disk an image file  
my_image.write("file_name_explicit_extension.gif");  

#include <windows.h>  
#include <wand/magick_wand.h>  
   
void test_wand(void)  
{  
         MagickWand *m_wand = NULL;  
          
         int width,height;  
          
         MagickWandGenesis();  
          
         m_wand = NewMagickWand();  
         // Read the image - all you need to do is change "logo:" to some other  
         // filename to have this resize and, if necessary, convert a different file  
         MagickReadImage(m_wand,"logo:");  
          
         // Get the image‘s width and height  
         width = MagickGetImageWidth(m_wand);  
         height = MagickGetImageHeight(m_wand);  
          
         // Cut them in half but make sure they don‘t underflow  
         if((width /= 2) < 1)width = 1;  
         if((height /= 2) < 1)height = 1;  
          
         // Resize the image using the Lanczos filter  
         // The blur factor is a "double", where > 1 is blurry, < 1 is sharp  
         // I haven‘t figured out how you would change the blur parameter of MagickResizeImage  
         // on the command line so I have set it to its default of one.  
         MagickResizeImage(m_wand,width,height,LanczosFilter,1);  
          
         // Set the compression quality to 95 (high quality = low compression)  
         MagickSetImageCompressionQuality(m_wand,95);  
          
         /* Write the new image */  
         MagickWriteImage(m_wand,"logo_resize.jpg");  
          
         /* Clean up */  
         if(m_wand)m_wand = DestroyMagickWand(m_wand);  
          
         MagickWandTerminus();  
}  

#include <windows.h>  
#include <wand/magick_wand.h>  
   
void test_wand(void)  
{  
         MagickWand *m_wand = NULL;  
         PixelWand *p_wand;  
         int w,h;  
   
         MagickWandGenesis();  
   
         /* Create a wand */  
         m_wand = NewMagickWand();  
         p_wand = NewPixelWand();  
   
         // Change this to whatever colour you like - e.g. "none"  
         PixelSetColor(p_wand, "blue");  
         /* Read the input image */  
         MagickReadImage(m_wand,"logo:");  
         w = MagickGetImageWidth(m_wand);  
         h = MagickGetImageHeight(m_wand);  
         MagickSetImageBackgroundColor(m_wand,p_wand);  
         // This centres the original image on the new canvas.  
         // Note that the extent‘s offset is relative to the  
         // top left corner of the *original* image, so adding an extent  
         // around it means that the offset will be negative  
         MagickExtentImage(m_wand,1024,768,-(1024-w)/2,-(768-h)/2);  
         MagickWriteImage(m_wand,"logo_extent.jpg");  
   
         /* Tidy up */  
         m_wand = DestroyMagickWand(m_wand);  
         p_wand = DestroyPixelWand(p_wand);  
         MagickWandTerminus();  
}