This is going to result in a pretty ugly thumbnail because you're missing the hints java needs to do high quality resizing. Java's shrinking also doesn't really have a nice smoothing mode.
I'd actually recommend you look into https://github.com/mikera/imagez. It has a resize function in core which does what you want. It uses Scalr internally which has some good quality options. As for why your code isn't working, it's hard to say. Can you try just writing out the file you read (before resizing) and make sure that it's actually loaded correctly? On Thu, Feb 27, 2014 at 5:04 PM, larry google groups < lawrencecloj...@gmail.com> wrote: > I wanted to see what Format strings I am allowed, so at the repl: > > > user> (import 'javax.imageio.ImageIO) > javax.imageio.ImageIO > > user> (require '[clojure.pprint :as pp]) > > user> (pp/pprint (javax.imageio.ImageIO/getReaderFormatNames))["BMP", > "bmp", "jpg", "JPG", "wbmp", "jpeg", "png", "JPEG", "PNG", "WBMP", "GIF", > "gif"] > > (fs/extension) was returning ".JPG" with a period. I thought that might be > the problem so I removed it: > > (defn make-thumbnail [filename path-to-new-file-including-file-name width] > {:pre [(= (type filename) java.lang.String) > (fs/exists? filename) > (= (type path-to-new-file-including-file-name) java.lang.String) > (number? width)]} > (println " we will write thumbnails to here: " (str > path-to-new-file-including-file-name)) > (let [ext (st/replace (fs/extension filename) #"\." "") > img (get-file-as-image filename) > imgtype (java.awt.image.BufferedImage/TYPE_INT_ARGB) > width (min (.getWidth img) width) > height (* (/ width (.getWidth img)) (.getHeight img)) > simg (java.awt.image.BufferedImage. width height imgtype) > g (.createGraphics simg)] > (.drawImage g img 0 0 width height nil) > (.dispose g) > (pp/pprint simg) > (println "the extension we use:") > (pp/pprint ext) > (javax.imageio.ImageIO/write simg ext (io/as-file > path-to-new-file-including-file-name)))) > > So the final println gives me: > > the extension we use: > "JPG" > > and yet now I get: > > Exception in thread "Thread-1" javax.imageio.IIOException: Invalid > argument to native writeImage > at com.sun.imageio.plugins.jpeg.JPEGImageWriter.writeImage(Native Method) > > which is surprising since the Format string, without the period, should be > more correct. > > > > > > On Thursday, February 27, 2014 4:47:31 PM UTC-5, larry google groups wrote: >> >> >> Hmm, I made it a little further. Now I am trying to write a thumbnail to >> disk. I have copied the code from StackOverflow. I am using this function: >> >> (defn make-thumbnail [filename path-to-new-file-including-file-name >> width] >> {:pre [(= (type filename) java.lang.String) >> (fs/exists? filename) >> (= (type path-to-new-file-including-file-name) java.lang.String) >> (number? width)]} >> (println " we will write thumbnails to here: " (str >> path-to-new-file-including-file-name)) >> (let [ext (fs/extension filename) >> img (get-file-as-image filename) >> imgtype (java.awt.image.BufferedImage/TYPE_INT_ARGB) >> width (min (.getWidth img) width) >> height (* (/ width (.getWidth img)) (.getHeight img)) >> simg (java.awt.image.BufferedImage. width height imgtype) >> g (.createGraphics simg)] >> (.drawImage g img 0 0 width height nil) >> (.dispose g) >> (pp/pprint simg) >> (javax.imageio.ImageIO/write simg ext (io/as-file >> path-to-new-file-including-file-name)))) >> >> >> This line: >> >> (println " we will write thumbnails to here: " (str >> path-to-new-file-including-file-name)) >> >> shows me this, which is the path I want: >> >> we will write thumbnails to here: /Users/larry/tma_files/ >> processed/b5838394-a86c-411f-b556-94b30c26a553IMG_1175_180.JPG >> >> This line: >> >> (pp/pprint simg) >> >> gives me: >> >> #<BufferedImage BufferedImage@7ac84a5b: type = 2 DirectColorModel: >> rmask=ff0000 gmask=ff00 bmask=ff amask=ff000000 IntegerInterleavedRaster: >> width = 125 height = 93 #Bands = 4 xOff = 0 yOff = 0 dataOffset[0] 0> >> >> I do not get any errors or exceptions, but nothing gets written to disk. >> Can anyone suggest why? >> >> If I look here: >> >> http://docs.oracle.com/javase/7/docs/api/javax/imageio/ >> ImageIO.html#write(java.awt.image.RenderedImage, java.lang.String, >> java.io.File) >> >> Writes an image using an arbitrary ImageWriter that supports the given >> format to a File. If there is already a Filepresent, its contents are >> discarded. >> Parameters:im - a RenderedImage to be written.formatName - a String containg >> the informal name of the format.output - a File to be written to.Returns: >> false if no appropriate writer is found. >> >> I am unsure what "false if no appropriate writer is found" means. I have >> added code to be sure that only jpeg, gif and png files get to this >> function. >> >> Any suggestions why nothing gets written to disk? >> >> >> >> >> >> >> >> >> >> On Thursday, February 27, 2014 4:09:10 PM UTC-5, larry google groups >> wrote: >>> >>> >>> Ah, I see what happened. There was a Microsoft Word document in my >>> folder of images. It was causing the problems. I had no error handling for >>> non-images. >>> >>> >>> >>> On Thursday, February 27, 2014 3:52:09 PM UTC-5, Aaron Cohen wrote: >>>> >>>> On Thu, Feb 27, 2014 at 3:44 PM, larry google groups < >>>> lawrenc...@gmail.com> wrote: >>>> >>>>> I tried this too: >>>>> >>>>> (ns tma-make-thumbnails.make-images >>>>> (:import >>>>> (java.util UUID) >>>>> (javax.imageio ImageIO) >>>>> (java.awt.image BufferedImage) >>>>> (javax.imageio ImageReader)) >>>>> >>>>> >>>>> >>>>> (defn get-file-as-image [filename] >>>>> {:pre [(= (type filename) java.lang.String) >>>>> (fs/exists? filename) >>>>> (fs/file? (io/as-file filename))] >>>>> :post [(do (pp/pprint %) true) >>>>> (= (type %) java.awt.image.BufferedImage)]} >>>>> (.read ImageIO (io/as-file filename))) >>>>> >>>> >>>> This is trying to invoke the "read" method of the Class instance >>>> representing "javax.imageio.ImageIO". This is surely not what you want. >>>> >>>> >>>>> but that only gives me: >>>>> >>>>> Exception in thread "Thread-1" java.lang.IllegalArgumentException: No >>>>> matching method found: read for class java.lang.Class >>>>> >>>>> I don't get why ImageIO is java.lang.Class after I imported it. >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> On Thursday, February 27, 2014 3:09:53 PM UTC-5, larry google groups >>>>> wrote: >>>>>> >>>>>> I have no background with Java so I tend to suffer pain when dealing >>>>>> with it. I am trying to create a thumbnail for an image, but my code dies >>>>>> on the :post assertion of this function: >>>>>> >>>>>> (defn get-file-as-image [filename] >>>>>> {:pre [(= (type filename) java.lang.String) >>>>>> (fs/exists? filename) >>>>>> (fs/file? (io/as-file filename))] >>>>>> :post [(do (pp/pprint %) true) >>>>>> (= (type %) BufferedImage)]} >>>>>> (javax.imageio.ImageIO/read (io/as-file filename))) >>>>>> >>>>> >>>> >>>> This is the correct syntax for invoking a static method of a class. I'm >>>> not sure why it's not working for you. What kind of file are you trying to >>>> load? >>>> >>>> >>> -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/groups/opt_out. > -- You received this message because you are subscribed to the Google Groups "Clojure" group. 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