ImageJ: What is the best way to add watermark to image?
I use two images the original image and the watermark image. The problem (in watermark image)is that I cannot change the opacity of the text without changing the opacity of the background. Note: the background transparency is 100% if I did not change opacity of the text
My recommendation is to use this tool: http://www.paintshoppro.com/en/pages/watermark-photos/ to add watermark to your photos, because sometimes watermarks can make your photos safer, but they can also be very easily removed, so your back to where you started. if you do it with that tool and make a transparent watermark, it wouldn't disturb the concept of the photo, but would also be much harder to remove.
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This question is related to What is the smallest possible valid PDF?, but goes one step further: I'd like a PDF file that is as small as possible, but also invisible.
That means:
it contains no text or other objects (or if that's not possible, only completely transparent ones), and
it has no background (or if that's not possible, a completely transparent background).
When I open this file in a compliant PDF viewer, the background color of the viewer panel should show through completely, and when I embed it in a document on top of other elements, only these other elements should show.
PDF pages have no background color by default (if you need an explicit background you have to draw a colored rectangle that covers the entire page).
PDF viewers will use a default white background to simulate a paper page, so the actual background depends on the PDF viewer.
When you place a PDF page on top of another one it will not block the underlying content if it does not have an explicit background.
I have to put an image (.png) into a pdf file using LibHaru. The image has a transparent background due to which it looks quite awkward (black background) into the pdf file.
How can I put this image (with transparent background) properly using C++ LibHaru?
You need to split your PNG file into two images: one for color pixels and another one for opacity values. Then you need to add the color image into PDF with specifying the second as SMASK property.
See 4.8.4 Image Dictionaries in PDF specification for more details.
You can use HPDF_Image_AddSMask method for this.
I'm using a webview to display a PDF.
The webview displays the PDF at it's actual size which is a little smaller than the size of the webvieww itself, revealing the scroll view underneath it.
I've tried setting the Webview to opaque and setting it's background color to another color, which works fine and dandy in the simulator, but fails to change the color on the device. On the device it changes the color of the background of the view behind the scroll view, this can be seen when the PDF is pulled all the way down.
I've also tried setting all the UIView's backgrounds, by iterating through the subviews but to no avail.
I've updated a diagram to help illustrate which area I'd like to color.
Uploaded Diagram
You really shouldn't mess around with UIWebView's internals.
They can change anytime and your code might just crash on the next version of iOS.
If you need more control about pdf display, you might wanna take a look at other possibilities to show pdf, like using the CGPDFDrawPage* functions. Of course they are pretty low-level and it's a lot of work required until you can get fast page display, zooming, etc all right.
I want to get a transparent background or no background for my images. I tried the '-background none' option and also the 'transparent' option, but the background image remains white. How can I achieve this?
Please suggest.
If you are using Imagemagik then the command is:
convert input.gif -transparent white output.gif
However, it will only work with a pure white background and not a shade of white.
There are alternative and easier ways to do this with IrfanView or The Gimp or Photoshop (more on that below).
This article mentions that you may be using convert.exe that comes with Windows rather than ImageMagicks Convert.exe in which case you should use the full path for Convert.exe.
http://www.imagemagick.org/discourse-server/viewtopic.php?f=1&t=10665
If you are trying to achieve this from CSS then you misunderstand the CSS property.
The css property 'background' refers to an html elements background color. I.e. <p> <div> <body> whatever.
more here http://www.w3schools.com/css/css_background.asp
If you are referring to the image opacity property, that refers to how "see-through" an image should be. more here:
http://www.w3schools.com/Css/css_image_transparency.asp
The only way to get a transparent background in an image is to make the background of the image transparent using either the PNG (preferred) or GIF formats. For this you can use IrfanView and save a picture as PNG, select the "save transparency" property and select the color from the image you want to be transparent or you can use Photoshop or The Gimp do the same. Example for IrfanView here http://llizard.etherwork.net/cwc/transp_irfanview.html
The Gimp example here http://aplawrence.com/Linux/crousegif.html
whats the format of your images? Try using png format
I've been working on some custom graphics controls, and I found this weird problem with windows 7 rendering my button controls. I've used Photoshop to delete the pixels in the background all around the button image I'm using, then saved it as a GIF, and imported it into VS to use as the background image of my button. When windows XP renders it, it is fine, but when windows 7 renders it, all 4 corners have an odd white border around them.
You can barely see them in this pic, but they are much more apparent when looking at them on the client PC's.
Is there something wrong with the way I am transfering the image? should I not use a gif? is there something wrong with the way I am displaying it on the button? What can I do about it?
GIF was a bad choice, it can only render images with 256 colors. You need all the colors you can get to make the anti-aliasing work properly. Use PNG.
You will also need to make sure that the background color of the container is the same as the one you used in Photoshop, the anti-aliasing pixels will otherwise have the wrong colors. And you cannot stretch the image, that will also stretch the anti-aliasing pixels, ruining the effect.