I'm using Visual Studio icon library (VS2008ImageLibrary), there are some BMP files with a pink background. How can I make the pink background become transparent? What software can I use to do this? Any free one?
Thanks
I used IrfanView's batch conversion tool. It's still some work, because you have to click the pink area on every single icon instead of just specifying pink as transparent color, but it worked. It would be easy to write a simple conversion tool using GDI+ though, which I considered as well.
Note that even though you can use them then as transparent images, many of them unfortunately still have ugly edges when you render them on a dark background or use them as overlay. If you just want very few of them, consider tweaking them individually if you think you'll not always have a bright background.
You can try it online provided you can transform your bmp into a gif first.
Or you can grab PAINT.Net (freeware), and apply a transparent background by following this video instructions.
You can do it by using ImageMagick convert:
convert input.png -transparent magenta output.png
By the way, it is not pink, its magenta colour.
While I don't know the modern .NET answer to your question, it's worth noting the historical reason for these bitmaps with magenta backgrounds:
Back in the Win32-only days, there were some Common Controls (like the Toolbar, and ListView) that took these bitmaps and a colour to be treated as transparent, and then rendered that colour as transparent. I imagine that, behind the scenes, they used functions like TransparentBtl.
I know it's something related to Form.TransparencyKey
but I donno what is exactly that pink, you have to know the exact RGB / system or Web color.
if you know please share us
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I am trying to use a sprite sheet for a game I am building with Javascript.
I noticed that many sprite sheets have colored background. In this case I am trying to use a image with pink background. I understand that in the old days this was common. But I am using the canvas element in Javascript and drawing to it.
I would like to remove the pink background.
I have tried to remove it with Photoshop and the magic eraser tool:
The arrows are good. But the problem is the snow. The snow has some transparency on them so it is mixed with the solid pink color and the edges look ugly.
Does anyone know a way to fix this? I was thinking maybe I could upload the image to a program that actually requires the pink background (like in the old days) and then export it as transparent. But I do not know of such a program.
I need to convert an image to greyscale except for a single color. For example, if there is some red in the image (like a red bus), this will remain in color, but the rest of the image will remain in black & white.
I think I should be able to do a rudimentary job of this by going over each pixel individually, such as here: http://brandontreb.com/image-manipulation-retrieving-and-updating-pixel-values-for-a-uiimage . I am assuming I would just leave certain pixels alone if their red component was above a certain amount, and green/blue was below a certain amount. Otherwise, set the pixel to grayscale. Is this a good approach?
I'm more interested in whether or not it is possible to do to the live camera input, such as with a Core Image filter, or using GPUImage, but I haven't been able to find any suitable filters. Any suggestions?
Update:
This seems to be possible using GPUImage with a GPUImageLookupFilter, as per: https://stackoverflow.com/a/19340583/334982
I've created a lookup.png file in Photoshop, by dropping the Saturation for all colours except red to 0. This works ok, but it doesn't seem to grey out all colours. For example, my skin still looks fairly skin coloured, and my brown table is still fairly brown.
I wish to have a transparent terminal.
In order the view the letters without increasing the font size, I would like to have a contrast by coloring the text's background.
Does anyone know of a way to do this? Perhaps installing a special font?
Your best bet would be to use bright colored text. I was just experimenting and it seems like a good, bright red stands out on most backgrounds. You can also experiment with the blur effect your terminal has. A higher blur will allow for more background contrast. I did not see a way to color the text's background color itself though.
Is there any software, plugin or technique that would allow creating/exporting PNG-like GIFs with smooth transparent edges, at least for smaller images like bullets or buttons.
I really have to use GIFs sometimes for IE6 so it'd would be great to know if such a tool exists?
Thanks
No, the GIF format does not support alpha-channel transparency like PNG does. You can only select one out of the 256 possible colors in a GIF to be transparent.
If you know roughly what color the background will be, the best you can do is create the GIF with the same background you plan to use it on, then select the background color as transparent. The smooth edges will look smooth against that specific background, but horrible against other colors.
The edges in a PNG are smooth because of anti-aliasing, and thus, variable opacity. The GIF format doesn't support this, so unfortunately no there isn't a way to do it.
GIF doesn't have an alpha channel like PNG, so you can't get smooth transparent edges. The alpha channel specifies how transparent each pixel is, so you could have half-transparent pixels for example. GIF on the other hand is limited to 8 bit colors and one of them is designated as the transparent color.
yes, a GIF can be transparent, just use png transparent frames and when embedded in css it would have a transparent background.
background: url(../images/mundog.gif) no-repeat;
As far as I recall (I've not used GIFs for quite some time), a GIF doesn't have a variable transparency - a pixel is either transparent or not.
You could simulate transparency by blending with the background image, but that would rely on having a static, defined background.
The modern solution for this is using WebP instead of GIF.
WebP supports both animation and an alpha channel, as well as lossless compression.
It's well-suported by browsers nowadays.
Using images of articles of clothing taken against a consistent background, I would like to make all pixels in the image transparent except for the clothing. What is the best way to go about this? I have researched the algorithms that are common for this and the open source library opencv. Aside from rolling my own or using opencv is there an easy way to do this? I am open to any language or platform.
Thanks
If your background is consistend in an image but inconsistent across images it could get tricky, but here is what I would do:
Separate the image into some intensity/colour form such as YUV or Lab.
Make a histogram over the colour part. Find the most occuring colour, this is (most likely) your background (update) maybe a better trick here would be to find the most occuring colour of all pixels within one or two pixels from the edge of the image.
Starting from the eddges of the image, set all pixels that have that colour and are connected to the edge through pixels of that colour to transparent.
The edge of the piece of clothing is now going to look a bit ugly because it consist of pixels that gain their colour from both the background and the piece of clothing. To combat this you need to do a bit more work:
Find the edge of the piece of clothing through some edge detection mechanism.
Replace the colour of the edge pixels with a blend of the colour just "inside" the edge pixel (i.e. the colour of the clothing in that region) and transparent (if your output image format supports that).
If you want to get really fancy, you increase the transparency depending on how much "like" the background colour the colour of that pixel is.
Basically, find the color of the background and subtract it, but I guess you knew this. It's a little tricky to do this all automatically, but it seems possible.
First, take a look at blob detection with OpenCV and see if this is basically done for you.
To do it yourself:
find the background: There are several options. Probably easiest is to histogram the image, and the large number of pixels with similar values are the background, and if there are two large collections, the background will be the one with a big hole in the middle. Another approach is to take a band around the perimeter as the background color, but this seems inferior as, for example, reflection from a flash could dramatically brighten more centrally located background pixels.
remove the background: a first take at this would be to threshold the image based on the background color, and then run the "open" or "close" algorithms on this, and then use this as a mask to select your clothing article. (The point of open/close is to not remove small background colored items on the clothing, like black buttons on a white blouse, or, say, bright reflections on black clothing.)
OpenCV is a good tool for this.
The trickiest part of this will probably be at the shadow around the object (e.g. a black jacket on a white background will have a continuous gray shadow at some of the edges and where to make this cut?), but if you get this far, post another question.
if you know the exact color intensity of the background and it will never change and the articles of clothing will never coincide with this color, then this is a simple application of background subtraction, that is everything that is not a particular color intensity is considered an "on" pixel, one of interest. You can then use connected component labeling (http://en.wikipedia.org/wiki/Connected_Component_Labeling) to figure out seperate groupings of objects.
for a color image, with the same background on every pictures:
convert your image to HSV or HSL
determine the Hue value of the background (+/-10): do this step once, using photoshop for example, then use the same value on all your pictures.
perform a color threshold: on the hue channel exclude the hue of the background ([0,hue[ + ]hue, 255] typically), for all other channels include the whole value range (0 to 255 typically). this will select pixels which are NOT the background.
perform a "fill holes" operation (normally found along blob analysis or labelling functions) to complete the part of the clothes which may have been of the same color than the background.
now you have an image which is a "mask" of the clothes: non-zero pixels represents the clothes, 0 pixels represents the background.
this step of the processing depends on how you want to make pixels transparent: typically, if you save your image as PNG with an alpha (transparency) channel, use a logical AND (also called "masking") operation between the alpha channel of the original image and the mask build in the previous step.
voilà, the background disappeared, save the resulting image.