What would be the way to draw a triangular button on the iPhone. It would be nice if I could also change its parameters (backgroundcolor, font etc..) as with the regular buttons.
Ideally I would like equilateral triangles.
take a look at this post: http://iphonedevelopment.blogspot.com/2010/03/irregularly-shaped-uibuttons.html
You could transform you button/view using core animation 3d transform. I am not sure how it will look like inside of it. but you surely can get a triangle form view.
You can apply a rotation in 3D (arround X or Y axis, not Z) with a large enough angle that it looks like a triangle.
An alternative approach is to make it look like triangular. You probably not need it TO BE triangular. So, maybe by setting a triangular look like image or maybe by hiding part of the button with (2D) rotated view or layer.
If you are not changing too much the background images of your buttons, I suggest to put in the resources, some .png file you create using photoshop for example, in which the triangular part has full opacity and the remaining areas are full transparent.
Then create UIImage using the method : [UIImage imageNamed:file_path_inside_resources_folder] and set it as background image for your button.
Note that you need to do the work only once, since the UIButton will resize the picture according to its own frame dimensions.
Regards
Meir Assayag
Related
I need a UIImageView initialized with an image that rotates around its own axis in the same way it does in this
GIF example.
My task is actually a little more complicated because I also need to turn a flat image into a thick, coin-like 3D image, but I won't bother anyone here with that. The only thing I want to know right now is whether it's possible to animate a UIImage like the example above, and if so, then how do I do it?
I'm trying to achieve a sort of dynamic UIView masking effect. Here is a sketch:
So as you can see, I'm trying to create a UIView that can effectively cut through an image to reveal the image behind it. I already know how to return an image with a mask statically, however I would like the "revealer" to be draggable (I'll use pan gesture) and live.
Does anyone have any ideas or starting points on how to achieve this? Thanks
(NOTE: My demo says White layer, but I'd actually like to show another image or photo).
masking an image is not that difficult.
This link shows the basics.
http://iosdevelopertips.com/cocoa/how-to-mask-an-image.html
But personally I think i would make 2 UIImage views and crop the content of the draggable UIView. I'm not sure but I would expect that clipping and panning the second image will be less computationally expensive then applying the mask and will get you a better frame rate.
So I would do: UIImageView of the full image. A UIView on top of it with a white and some transparency setting to make it look white, then a UIImageView with the image either places or cropped so that only the correct section is showing.
How can a bounding box be created for a UIImageView that is not a CGRect?
I would like to have objects in my view which should display images as well as detection collisions.
The issue is I would like these object to be whatever shape they are rather than fitting them into a CGRect and detecting collisions on areas which are inside the box but are nit the actual image.
How does one achieve this?
This is a non-trivial problem. But the basics are a CGRect is a rectangle and a hit test inside of a rectangle is fairly easy to understand. However, you sound like you want a more complex shape. UIImageView displays an image. It does not have any idea about what shape you want to use for your collision test. So you are going to have to tell it.
One easy thing to do is to look at the alpha/transparent values of the display image to create a shape. So to answer the question is a point hitting an image we figure out the location of point in the image and return true if the alpha is greater than 0. If you do this you can create any image with a transparent background and the code will just work.
If that will not work for you then can can also run a hit test on a point and a polygon this post covers that in detail.
How can I determine whether a 2D Point is within a Polygon?
I want to implement dialog borders that scale to the size I require the dialog to be. Perhaps there is a better more conventional name for this sort of thing. If there is, if someone would edit the title, that'd be great.
Anyhow, I'd like to do this so I can have dialogs of any size without the visual artifacts that come with scaling border art to small, large, or wacky unproportional dimentions. I have a few ideas on how this is done, but am not sure which is better for iphone. I have a few questions.
1) Should I make a containing view object that basically overloads its drawRect method and draws the images where they should be at their appropriate scale when the method is called, or should I main a containing view object that simply contains 8 UIImageViews? I suspect the latter approach won't work if I need to actively scale the resulting dialog class like in an animation.
1b) If overloading drawRect is the way to go, does someone have some sample code or a link to an example that demonstrates drawing an image directly from drawRect()?
2) Is it generally better to create
a) a 3 x 3 image where the segments are in their appropriate 1x1 grid of the image? If so, is it simple to draw from a portion of this image onto my target view in drawRect (if the former assumption is correct that I should use drawRect)?
b) The pieces separately in 8 different files?
UPDATE:
To clarify, the idea is to take any customized border art and be able to stretch the 2nd, 4th, 6th, and 8th cell (in a 3x3-cell grid) to form a border of any size with just those assets. Stretching just a plain image would result in distortion of the corners, so I'd like to stretch those even numbered cells as needed and tack on the corners so there is no distortion. I'd seen this done before so thought it might be a standard thing and have a standard naming to it other than what I called it.
Anyhow, I was advised that adding 8 UIImageViews to a container would not be as efficient as drawing the UIImages on the fly in drawRect so took that approach using CGContextDrawImage() after applying the necessary transformations to the context to translate and scale the Y. Because this function draws from the bottom left corner of an image but onto a top-left origined UIView, the image is upside down without the Y axis invert. I noticed the suggestion to use UIImage functions like drawAtPoint works as well and similarly but for the invert since UIImage draws in the same orientation as UIViews. I will continue my implementation with the former and see how it goes, but one other question.
Would someone happen to know which of these approaches is more efficeint, faster, etc?
I'm not sure I follow, but here's my best shot at an answer...
Using drawRect: or adding individual UIImageViews to a parent view is entirely up to you. UIImageView gives you a bit of encapsulated functionality for free, but otherwise they are the same as far as appearances go.
If you do want to go the drawRect route, you just need to use UIImage's drawAtPoint: method. Do the math for where you want it to be, and draw it. You can calculate your points based on the parent view's dimensions.
As far as scaling, it's impossible to resize these images without scaling them, so I'd plan ahead and make your originals as large or larger than you ever expect to display them.
Hope that helps a little?
Cheers
If you want a border on a dialog box, assuming the box is a UIView (or subclass), then set the layer's border properties and let the system draw the border for you.
#import <QuartzCore/QuartzCore.h>
// ...
view.layer.borderWidth = 2;
view.layer.borderColor = [UIColor whiteColor].CGColor;
view.layer.cornerRadius = 0; // 0=square corners, >0 for rounded
I m trying to do slideshow effect in iPhone as like in iTunes. One Image at the middle and the others at the left and ride side arranged in the manner of floppies in rack. but I not even a single clue for that. Can any one help me out?
I'm guessing that you're talking about "coverflow" rather than "slideshow"... if that's right, there are some libraries to help you: here's one I found by searching for "coverflow replacement":
http://apparentlogic.com/openflow/
You can achieve this effect using the .transform property of CALayers. All iPhone UIViews have a CALayer, and you can apply 3D perspective transformations using a transform matrix like this:
CATransform3D m = CATransform3DIdentity;
m.m34 = -0.006;
[[containerView layer] setSublayerTransform: m];
The views within containerView will now have a perspective distortion applied! Instant coverflow affect. Just move the views to the left and right by changing their frames.