I need to use some existing images with some white icon glyphs inside them and extract only the glyph part . Imagine the iPhone's Phone.app icon, which is green around, and has a white telephone icon in the middle. I would need to extract only the telephone icon, without the green background (and keep a transparency around it) .
I tried using CGDataProviderCopyData and iterate through the pixel values and change them,
but I am not familiar with graphics techniques and I had no luck.
Any help would be appreciated.
Do you have a fixed amount of images that you want to extract the while glyphs from or is it going to be continuous?
If its a fixed amount then that's a job for photoshop and not a question for here. If its for a stream of continuous images then I would suggest looking at the pixel values again.
A white pixel is (255,255,255) if you want to include near white pixels in your search you could include any pixels above a certain threshold. For example any pixels with all three values above 230.
So.. (<230,<230,<230)
Hope this helps :)
Related
I have been searching on youtube and google but still haven't found anything that fits my question or that I don't understand. Does anyone know how to extract coordinates from dots on an image (what program is best and/or how to do it). When looking at the image, you can see some black dots that can differ per image. I would like to extract the x,y coordinates from all the black dots as a coordinate system with the 0 point in the middle (surrounded by the red circle).
Thank you in advance!
The image with the black dots
I have two identical sized images that I would like to work with. One image is in color, the other is in black and white. I need assistance on stacking the color image directly over the black and white image. After that, I would like to be able to remove sections of the top photo to reveal the image underneath.
Can someone point me in the right direction on how to accomplish this?
Here is something that may help:
http://forums.devshed.com/php-development-5/how-do-i-merge-various-images-into-one-using-gd-502604.html
Especially the part that talks about adding watermarking.
You will have to add transparent areas to the top image before combining them.
lee
I asked this question on the Graphic Design site, but it includes a programming component that might be better answered here.
Specifically, I have a bunch of photographic crayon images. I would like to remove the color from one to produce a neutral image that I can load into an iPhone app that I'm writing and dynamically color. The crayon images have dark regions (shadows) and light regions (shine) which I would like to preserve. I will be dynamically coloring it with many different colors, ranging from white to rainbow colors to black.
My first inclination is to turn the image into a grayscale image and then somehow turn the color channel into an alpha channel, and change the color of all pixels to black. Then I could use it as a mask. However, this would only preserve the shadows, and I would lose all the highlights.
Any ideas?
Two options come to mind:
Make a grayscale version that could be tinted as you said, with the shadows and highlights simply white and gray.
Make an outline, i.e. an image with alpha that had 0% opacity in the colored parts, say 10% white over the highlights, 10% black on the shadows, and 100% black/dark gray for the lines/edges. The idea being that you could put any color under the outline and it would look right.
I have never seen this issue before, its very strange. Just wondering if anyone else has come across this too.
I have added a sprite to my game, its supposed to be the top left corner of a box to put text on to. I want to make it scalable without loosing anything so i have it broken up into sections. In the image above the one on top is the image itself, and then the one on the bottom is the image when its being drawn in the iPhone simulator.
Any idea why the last column of pixels on the right are altered? I have not scaled the image at all.
I don't know about Cocos2D, but in general terms what you've done here is to draw the image at a position that isn't an exact multiple of one pixel.
Consequently even without scaling you have resampled the image across a grid that doesn't coincide with the original image data, causing all pixels to be a bit off. It's just the right-hand edge is the most obvious case, since the resampling leaves you with a partial transparency here. But look at eg the two rows of purple pixels in the border: they're not the same, because your vertical alignment is off as well, causing a small amount of colour from the grey border below it to bleed into the lower row of purple.
Ok I actually figured it out this time. Cocos2D adds a bit of antialiasing to CCTextures. To stop it from doing this you need to call this:
[[mySprite texture] setAliasTexParameters];
to turn it back on you call this:
[[mySprite texture] setAntiAliasTexParameters];
The image on the right is the one that I produced in photoshop. I then stripped all text and put it in an image view, as soon as I did that there was a change in colour and the vertical line lost it sharpness. Has anyone else run into a similar problem? What do I do?
alt text http://grab.by/1DuZ
Are the dimensions correct? Is the position of the image an integer? If these cases antialiasing will slightly blur your image.
One thing to be careful of is that if your image is an odd number of pixels in either dimension then centering it onscreen will cause it to be misaligned. Imagine if you had a 1x1 image (just one pixel) and tried to center it perfectly onscreen. It can't be done because the screen is an even number of pixels wide and high. This is why it's best to always use even dimensioned images whenever possible.