Code helper class for compressing images in Java

 

Package cn.com. images; import Java. AWT. graphics; import Java. AWT. image; import Java. AWT. image. bufferedimage; import Java. io. file; import Java. io. ioexception; import Java. math. bigdecimal; import Java. math. mathcontext; import Java. util. arraylist; import javax. imageIO. imageIO;/***** operate images ** @ author chenzheng_java * @ since 2011/7/29 **/public class imagehelper {Private Static imagehelper = NULL; public static imagehelper getimagehelper () {If (imagehelper = NULL) {imagehelper = new imagehelper ();} return imagehelper ;} /***** scale the image according to the specified scale ** @ Param sourceimagepath * Source Address * @ Param destinationpath * after the image size is changed * @ Param scale, such as 1.2 */public static void scaleimage (string sourceimagepath, string destinationpath, double scale, string format) {file = new file (sourceimagepath); bufferedimage; try {bufferedimage = ImageIO. read (File); int width = bufferedimage. getwidth (); int Height = bufferedimage. getheight (); width = parsedoubletoint (width * scale); Height = parsedoubletoint (height * scale); image = bufferedimage. getscaledinstance (width, height, image. scale_smooth); bufferedimage outputimage = new bufferedimage (width, height, bufferedimage. type_int_rgb); graphics = outputimage. getgraphics (); graphics. drawimage (image, 0, 0, null); graphics. dispose (); ImageIO. write (outputimage, format, new file (destinationpath);} catch (ioexception e) {system. out. println ("An error occurred while compressing the image using the scaleimage method"); E. printstacktrace ();}} /***** scale the image to the specified height or width * @ Param sourceimagepath Image Source Address * @ Param destinationpath: compress the image address * @ Param width: The scaled width * @ Param height: The scaled height * @ Param auto determines whether to automatically keep the original aspect ratio of the image. Example * @ Param Format: Image Format: JPG */public static void scaleimagewithparams (string sourceimagepath, string destinationpath, int width, int height, Boolean auto, string format) {try {file = new file (sourceimagepath); bufferedimage = NULL; bufferedimage = ImageIO. read (File); If (auto) {arraylist <integer> paramsarraylist = getautowidthandheight (bufferedimage, width, height); width = paramsarraylist. get (0); Height = paramsarraylist. get (1); system. out. println ("Auto Adjust ratio, width =" + width + "Height =" + height);} image = bufferedimage. getscaledinstance (width, height, image. scale_default); bufferedimage outputimage = new bufferedimage (width, height, bufferedimage. type_int_rgb); graphics = outputimage. getgraphics (); graphics. drawimage (image, 0, 0, null); graphics. dispose (); ImageIO. write (outputimage, format, new file (destinationpath);} catch (exception e) {system. out. println ("An error occurred while compressing the image using scaleimagewithparams"); E. printstacktrace () ;}}/*** converts data of the double type to an int type. The rounding principle ** @ Param sourcedouble * @ return */Private Static int parsedoubletoint (double sourcedouble) {int result = 0; Result = (INT) sourcedouble; return result ;} /***** @ Param bufferedimage the image object to be scaled * @ Param width_scale the width to be scaled * @ Param height_scale the height to be scaled * @ return a set, the first element is the width, and the second element is the height */Private Static arraylist <integer> getautowidthandheight (bufferedimage, int width_scale, int height_scale) {arraylist <integer> arraylist = new arraylist <integer> (); int width = bufferedimage. getwidth (); int Height = bufferedimage. getheight (); double scale_w = getdot2decimal (width_scale, width); system. out. println ("getautowidthandheight width =" + width + "scale_w =" + scale_w); double scale_h = getdot2decimal (height_scale, height); If (scale_w <scale_h) {arraylist. add (parsedoubletoint (scale_w * width); arraylist. add (parsedoubletoint (scale_w * Height);} else {arraylist. add (parsedoubletoint (scale_h * width); arraylist. add (parsedoubletoint (scale_h * Height);} return arraylist ;} /***** returns the three digits after the decimal point of two numbers A/B * @ Param A * @ Param B * @ return */public static double getdot2decimal (int, int B) {bigdecimal bigdecimal_1 = new bigdecimal (a); bigdecimal bigdecimal_2 = new bigdecimal (B); bigdecimal bigdecimal_result = values (bigdecimal_2, new mathcontext (4 )); double double1 = new double (bigdecimal_result.tostring (); system. out. println ("the double after division is:" + double1); Return double1 ;}}