I imagine that there are probably alternative, and possibly better, NConvert solutions using the available code options above. That problem doesn't arise with the GUI solutions you posted, I presume. Even when the background colour was 255 255 255, the paletted value wasn't pure white. It seemed to be necessary to determine the actual paletted colour in a test conversion so that that value could be set, the actual value depending on the bit depth valued entered. That seemed to work well for the letters I tested initially which were black and white scans (so no need to use 256 colours really) but failed when I tested a colour scan: the problem seemed to be that when the image was converted to paletted colour, nominally white canvas wasn't converted to pure white even when I reduced the colour depth right down to 8 colours. At a quick look the following options support transparency:Ĭode: Select all nconvert -32bits -colors 256 -transpcolor 255 255 255 *.PNG That could be useful if the need arose regularly, although that isn't my present use case. Having converted a letter and now done a further test I'm not sure if the result is actually better.Īfter posting yesterday, as an afterthought I checked the NConvert help file and found that it might be possible to create a batch file that would convert scans to transparent in a single operation. I'd done some tests using layers in Paint.NET which I've worked with a little recently, but then wondered if starting with a transparent foreground image of the letter might produce a better result, or have other advantages. I thought it might look better if the passages to be marked were highlighted by a single coloured block. My considered use case arises directly from my freely-admitted perfectionist personality trait: I need to prepare a file containing copies of a series of letters in which carefully selected text is highlighted I could of course easily use the highlighting tool in Adobe Acrobat, but I noticed that it can leave gaps between the lines marked. Thank you for your customary detailed response: not only possible, but a choice of methods. IDUX: What Are Index and Alpha Please let me know if I forgot about something!.Jesse O'Chapo: Developers Guide to Images.1 through 254 = gray mask = semi-transparent (translucent).0 = 100% black (R0/G0/B0) mask = fully transparent.This command adds a uniform alpha channel to an image: XnView Classic: Add alpha ( Tools → Batch Processing.You then need to specify the index number of the color you'd like to be (fully) transparent. The color depth of the input images has to be (reduced to) 8-bit (256 colors) or less for this method to work. XnView Classic: Set the transparency value to palette entry ( Tools → Options.This method basically works like the Fi lter → PhotoMasque add-on: You have to prepare a (grayscale) mask which is then “superimposed” on the input images. Supported output formats: BMP, ICO, PNG, TGA, … → Actions » Add action → Image → Add mask: mask.png) XnView MP: Use mask as alpha ( Tools → Batch convert.headings, text) to over 40 different languages, including English, French and German.Do you have a particular use case in mind? The integrated file operations such as copying, moving, creation of directories and files makes XnView the universal tool for graphics.Īn additional features is that XnView is available on many operating systems e.g. XnView lets you create the optimal defaults according to your needs and preferences, thereby letting you work in the most efficient manner. The connection to other widely used professional graphic programs e.g.Adobe Photoshop, can be done using 'Drag and Drop', clipboard or 'Open With' Menu option. Numerous image filters and effects for image processing are available. XnView can be run without installation.Īs well as offering easy image viewing, XnView also offers more advanced features such as contact sheet, multiple conversion (format and transformation), slide shows, screen capturing and Twain support (Windows) for scanners and digital cameras. This lets you keep an overview of the images available at the same time as letting you quickly view and select specific images. You simply navigate the directory structure as desired and any image files found in a directory are displayed in miniature (Thumbnails). The Image viewer (Browser) is similar to Windows Explorer. XnView can also display video formats, many digital camera formats and more exotic formats such as Amiga IFF and Calamus. XnView is able to read more than 500 different formats and then convert them to other formats such as GIF, BMP, JPG, PNG, multi page TIFF, HEIF, WebP, JPEG-2000, JPEG XL. With XnView you can quickly and easily view, process and convert image files. Welcome to XnView, the Universal Graphic Viewer and Converter.
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