Change color of the iPhone screen - iphone

I need to change the color of the iPhone screen when i touch on it. The only thing i need to do is to change the color of the area where i am touching. if i am placing a star on the screen as touch then only that area color will be changed.
Any idea about this?

Take a look at some of the Graphics and Animation iPhone SDK Samples - there are samples there that show how to paint with different colours and other samples of how to use user input.

Related

How to add effects to UILabel

I've been searching for that many time ago and I can't find a solution. I have a animated label that crosses the screen of the iPhone (like the title of a song does in the Music app.Well, I'd like to add the "fade in/out" effect like the music app has. The easy solution is open Photoshop and create this simple image and then add it up to the label. Well, under the label I have an image with black backgroud. The image can be zoomed in and then the image with the fade in/out effect can be seen, and it doesn't look well. Is there any possibility to do this programatically? Thanks
PD: if there's another possibility rather than doing this programatically, I'll apreciate the answer as well.
Edit: Here's the image capture of the problem
I'll approach it in a non-programming way.
The image reference you gave us for the Music app you seem to be emulating has a different gradient than the one you drew in the second image.
If you notice in the image, the gradient has not fully completed its transition from clear to black before the words are cut off. I would say in photoshop run the gradient from clear to 80% alpha black and then draw a 100% alpha black rectangle to finish it off as per image. The white is just showing you what it looks like without the black background.
Now as for the zooming. Correct me if I am wrong, but it sounds like you want a viewing window for the image so that once you have zoomed into it, it will fade to either side, but still be viewable/movable in the center. This means that the image has to be zoom-able, but once you have zoomed the "fade in/out" should not be zoom-able.
Just make sure you aren't scaling the fader by keeping it separate from the scrollView of your background image.

How to make view like in the image attached?

I want to implement the UI feature as in the image attached. The image is an screen shot form a Siemens App that is in App store. Here the bright portion can be rotated like wheel. I have gone through the link
http://www.raywenderlich.com/9864/how-to-create-a-rotating-wheel-control-with-uikit.
but I am not able to implement the feature as in image.
Following is the link to download the Siemens app.
http://itunes.apple.com/us/app/siemens/id452698392?mt=8
The simplest approach I can think of is to use two images. One would have the green and white detail display and one would be gray with a slight circular gradient, a lot of transparency, and a fully transparent segment.
The gray image would go on top and handle touch movement by rotating and taps according to its last stop position.

How to erase foreground image to make the background visible using OpenGLES?

I'm learning iPhone development specifically OpenGL ES 2. I'm trying to achieve an effect as in steam draw. I have a background image and a foreground image. When I move the finger over the foreground image the corresponding pixels of the foreground image are erased and the background does get visible. Can someone point me in the right direction on how to implement this? Some guide lines?
You can use GL_STENSIL_TEST when drawing foreground to exclude fragments you choose(or your finger ;))

Coloring Image in iPhone SDK

i am developing a iphone app. i have a background image lets say an airplane with black color out lines and from color palette user can pick a color and fill the region of airplane....any help, code , suggestion will highly be appriciated
A simple fill algorithm should do. just expand from the point you are on until you meet region end pixels
see http://en.wikipedia.org/wiki/Flood_fill you can also try googling for Boundary Fill algorithm
My first though was to have a UIView and a mask image on top of that with the plane but this only works in certain situations. If the shape of the plane does not change you could also change the color and then "fill" the plan in during the drawRect using functions like CGContextAddArc and CGContextAddRect.

How can I highlight an image on an iPhone?

I have a photo displayed on an iPhone. I would like to lower brightness of the photo at first, and when the user touches the photo, I would like to raise the brightness of the rectangular region near where the user touched, like this:
www.cottagearts.net/tut_images/tut_cropping_pse_06.jpg
Could anyone point me to a simple way of doing this?
While you can't actually adjust the brightness of the screen, you can put a semi-transparent image on the screen. I'd paint everywhere but where the user touched with an color that is black, but has X transparency, which is exactly what that image is showing that you linked to.
I'm no expert, but I've been trying to do something similar. You could implement this with layers. As Malfist suggested, you could make a black layer with a certain opacity and may the clicked part of it fully transparent or somesuch. Another option would be to do some image processing. I found an article here that I think will handle my highlighting issue:
http://arstechnica.com/apple/news/2009/03/iphone-dev-basic-image-processing-package.ars