The library pdfiumviewer might be helpful here. It is also available as nuget. Create a new winforms app. Add nuget “PdfiumViewer” to it. This will also add two native dll’s named “pdfium.dll” in folders x86 and x64 to your project. Set “Copy to Output Directory” to “Copy Always”. Try out the following code (change paths … Read more
Image img = ImageIO.read(new File(“test.jpg”)).getScaledInstance(100, 100, BufferedImage.SCALE_SMOOTH); This will create a 100×100 pixels thumbnail as an Image object. If you want to write it back to disk simply convert the code to this: BufferedImage img = new BufferedImage(100, 100, BufferedImage.TYPE_INT_RGB); img.createGraphics().drawImage(ImageIO.read(new File(“test.jpg”)).getScaledInstance(100, 100, Image.SCALE_SMOOTH),0,0,null); ImageIO.write(img, “jpg”, new File(“test_thumb.jpg”)); Also if you are concerned about speed … Read more
Old post, but for future reference: Inspired by this question and links found here, I’ve written a JPEGImageReader plugin for ImageIO that supports CMYK color models (both with original color model, or implicitly converted to RGB on read). The reader also does proper color conversion, using the ICC profile embedded in the JPEG stream, in … Read more
ImageMagick has Python bindings.
I believe it’s because the JPEG you’re working with is a progressive JPEG, which has a different mime-type.
CSS image-orientation: from-image from the specs https://www.w3.org/TR/css4-images/#the-image-orientation 6.2. Orienting an Image on the Page: the ‘image-orientation’ property image-orientation: from-image from-image: If the image has an orientation specified in its metadata, such as EXIF, this value computes to the angle that the metadata specifies is necessary to correctly orient the image. If necessary, this angle is … Read more
Ran into this one today, found this: https://www.imagemagick.org/discourse-server/viewtopic.php?t=20234 Based on that, these should all work: -flatten -alpha flatten -alpha remove I’m currently using the below for my specific case which works great: convert -thumbnail “1280×800>” -density 300 -background white -alpha remove in.pdf out.jpg
A more succinct way is to get the ImageWriter directly from ImageIO: ImageWriter jpgWriter = ImageIO.getImageWritersByFormatName(“jpg”).next(); ImageWriteParam jpgWriteParam = jpgWriter.getDefaultWriteParam(); jpgWriteParam.setCompressionMode(ImageWriteParam.MODE_EXPLICIT); jpgWriteParam.setCompressionQuality(0.7f); ImageOutputStream outputStream = createOutputStream(); // For example implementations see below jpgWriter.setOutput(outputStream); IIOImage outputImage = new IIOImage(image, null, null); jpgWriter.write(null, outputImage, jpgWriteParam); jpgWriter.dispose(); The call to ImageWriteParam.setCompressionMode(ImageWriteParam.MODE_EXPLICIT) is needed in order to explicitly set … Read more
Your code is correct, it seems that cv2.imread load an image with three channels unless CV_LOAD_IMAGE_GRAYSCALE is set. >>> import cv2 >>> image = cv2.imread(‘foo.jpg’) >>> print image.shape (184, 300, 3) >>> gray_image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) >>> print gray_image.shape (184, 300) >>> cv2.imwrite(‘gray.jpg’, gray_image) Now if you load the image: >>> image = cv2.imread(‘gray.jpg’) >>> … Read more
For the life of me, over the last 5 years, I cannot get imagemagick to work consistently (if at all) for me, and I don’t know why people continually recommend it again and again. I just googled how to convert a PDF to a JPEG today, found this answer, and tried convert, and it doesn’t … Read more