I am developing an iphone application which would let me modify the image by dragging other images over its top along with functionality that would let me choose a specific color from the image and replace it with some other color shades i choose. If anyone has some clue like how to actually implement it or some code, that would be great help for me to proceed in right direction
Thanks in advance :)
If you just want to overlay images, you can simply drag UIImageViews around and position them within the view hierarchy such that the appropriate images are overlaid one on top of the other.
For generating a new image out of those composited images, you may want to use something like CGContextDrawImage() within a UIView subclass's -drawRect: method or in a custom CGContext. You can also refer to these similar questions:
How can we combine images and get image object from this two images in iphone apps
Combining images
As far as selectively replacing a specific color within a UIImage, that's a commonly asked question here:
In a UIImage (or its derivatives), how can I replace one color with another?
How to make one color transparent on a UIImage?
Related
I have this image:
What I want to do is to add a UITapGestureRecognizer to this image (or I can split the image in the different parts it consists of and add for each part a UITapGestureRecognizer) in order to have different actions according to the leaf tapped. If I split the image in different images each for each leaf the UIImageViews will probably overlap and tapping on one will be recognized as a tap on another one. Having just one image implies knowing the points of the screen that belongs to a leaf rather than to another one.
Any clues on how to do it would be really appreciated.
Thanks
Change your behavior by examining the gesture recognizer's locationInView:.
If you handle the image as one unit, implement this in your gesture recognizer call back to decide which "leaf" (if any) was tapped.
If you handle the image as multiple images, you could also implement it in your callback, or you could also implement in, e.g., your delegate's gestureRecognizerShouldBegin: to suppress events for touches outside the leaf as drawn.
EDIT: I didn't realize that you might also be looking for assistance on figuring out whether a point lies within a leaf. #PhillipMills is correct on this point: we need to know how you are drawing the image.
FOLLOW-UP: This is somewhat outside my area of expertise.
The easiest approach (from a hit-testing standpoint) is to do what #PhillipMills suggested, using Quartz drawing and CGPathContainsPoint(). If you have detailed graphics that you need rendered as a PNG, you could certainly construct a simple path that would be (virtually) overlayed to allow hit testing.
Your other options, AFAIK, are to do hit testing mathematically, but you would basically be reimplementing CGPathContainsPoint() but without a path, or to employ various tricks that look at the color of the pixels at your touch point to do hit testing. Googling will turn up some useful results if you go this route, but honestly for a shape as simple as what you've drawn, just use some UIBezierPath code to recreate in code.
Not sure if this will be helpful but if you get stuck on figuring out which leaf was clicked, you could use an old image map trick we used to use in CD-ROM projects for pixel accurate click tracking on images.
You have your full size image. Make a 25% (or less) scaled version of it. Fill each of the leaf regions you want to track clicks on with a different color; anything you want to ignore make black. When the full size image is clicked, get the x/y coordinates and scale them by the percentage of your scaled image. Then get the pixel color of the scaled image at the scaled x/y coordinate. By determining the pixel color you will know which leaf was clicked.
Sounds clunky but it works really well and is fast.
(all that said, I don't think alpha areas of images trigger the gesture recognizer - so breaking the image up would be less complicated/code intensive.)
If you can break the shape apart into the constituent elements, then you can put each into it's own layer and use the method discussed in this stackoverflow discussion to determine which was touched: Hit Testing with CALayer using the alpha properties of the CALayer contents
just like the popover in the attached screenshots, the popover allow user to change themes.
I know that there are some examples around but they are all using images to achieve this, make it hard to change themes.
I believe the app in the screenshots doesn't using images to do it.
thanks for any help!
In my Win background such skins (called "Flat" in Delphi and WinForms) were made by drawing in code: select a color, draw a line, select another color, draw a rounded rectangle and so on.
Also, it is necessary to introduce a class "ColorTheme" with a set of fields for every color used. You may have several ColorTheme instances and swap them when you need to change color theme.
I have an image with picture of a person and I want to let the user to pick some area of the person and change the color. But how can I best create a multi-mask image?
E.g. should the user be able the change the color for a leg or a hand.
I am using Titanium Appcelerator, and right now I had a solution with buttons placed over the image, which is not a pretty and accepted solution.
The Kitchensink example, has only one area which can be changed.
The only solution I found for working with sections of an image is to divide the image into different views then use a vertical or horizontal view to glue them together. Sounds like you took a similar approach using buttons.
Another option might be to use one of the jQuery image libraries within the webview. This most likely will have a performance penalty though.
I am implementing fun application.In which i want to animate some area(portion) of images.
I dont know how it possible.If u have any idea then please help me.
If you're looking to animate a portion of an image you could just create a smaller animation and put it at the right relative location inside a larger image.
If you want to know how to animate images in general, that's a different question entirely.
I have a png image file that is partly opaque and partly transparent. I display it in a UIImageView as a mask of sorts over another UIImageView layered behind it (as a sibling subview of a common superview). It gives me perfect borders around something painted using a finger on the lower UIImageView in my stack of UIImageViews. Perhaps there are better ways to do this, but I am new-ish, and this is the best way I came up with thus far. None the less, my app is in the App Store and now I want to enhance it to provide more images to use as the mask of sorts over the finger painting. But I don't want to bloat my bundle size by adding more static mask images as I did for the initial implementation. Not to mention I don't want to spend lots of time in photoshop making 100 masks. I'd rather programmatically change the color of the mask, without affecting the clear portion in the middle, which is not a simple regtangle or circle, but rather a complex shape. So my question is this: How can I change the colored portion of my loaded image without affecting the clear color portion in the middle? Is there a reasonably easy way to do this? Essentially I want to do what is described in this post (How would I tint an image programmatically on the iPhone?) without affecting the clear portion of my image. Thanks for any insights.
Have a look at the Tinted Image sample project. Try out the different modes until you get the effect you want.