I am trying to make an app that can annotate PDFs.
What I have done, is add the PDF through a UIWebview, so my main UIViewControllerhas a UIWebView Delegate.
What I am trying to do is put my drawing layer, which is a UIView over the top of my PDF view.
I have tried setting the background colour to "clearColour" and the opaque property to no, I still get a weird affect.
I think the issue might be because of drawing a bitmap onto the UIView, but I would still like some insight, or an example if one exists.
Thanks.
This is an image of the problem, the little white band at the top is the PDF, the white box is the UIView which I am drawing on.
The code I used for the "drawing code" is here, see "SmoothedBIView"
http://mobile.tutsplus.com/tutorials/iphone/ios-sdk_freehand-drawing/
Sorry, just noticed you had two questions. Again maybe this project can help you.
Related
My app is behaving sluggishly. If i pop up a UIActionSheet, for example, instead of rolling in smoothly, it stutters in over about 5 frames. I know ideally you should have as little amount of views on screen as possible, but that's what I've got anyway.
Any suggestions for speeding it up?
EDIT:
On my view i have:
Custom navigation bar in place of the regular one. It's a UIImageView, using an image file. It has a quartzcore shadow. It contains 3 buttons. 2 of these buttons have 2 UIImages each, for normal and highlighted, generated from code when the view is shown. The other button uses an image file for normal and for highlighted.
An image file for a background lies under that. On top of the background is a UITableView. By default, it doesn't have any cells (the user adds them). We'll ignore the cell, since it's slugging regardless of their being there or not.
The header of the tableview contains some labels, and an editable uitextview. The size of the header changes as more lines are added to the textview. It also has a background image, which is transparent to allow you to see the view's background image behind it. It's loaded from a file, and a texture image on top of that is also loaded from a file.
The footer is simply a background image loaded from a file with the same texture on top.
Andrew, I'm afraid you haven't been quite specific enough to isolate the exact problem. However there are a couple of things I have picked out. Firstly, check your table view is set to be opaque. Also try to design your app so your table cells can be opaque. I'm assuming your design will allow this. You need to really know how to optimise view rendering performance if you want your table and it's cells to appear translucent over other content and it may be you would need to develop your own custom specialised alternative to UITableView if that is something you really need to know (can be done but quite advanced stuff).
Also you mention using Quartz shadow. You should be able to use UIKit for drawing shadows around images, unless you have some specialist requirement. Are you sure you need to use Quartz for what you want to do? Apologies if you already know this, but if you are fairly new to iOS development and have been looking up how to do shadows, you may have found the Quartz API's for doing that and assumed that is the solution, when (depending on what you need) you will probably be better off staying with UIKit. As a general rule of thumb, only use Quartz if you are sure you can't do what you want to do with just the UIKit API's.
Another thing to check. If you are using Quartz, then you are probably getting getting the graphics context for the UIImage view and drawing on the views context in drawRect: depending on how your view hierarchy is configured, and if you have your navigation bar view set to be transparent over the top of the UITableView, then your custom drawRect implementation may be getting called unnecessarily with every animation frame and this would be a big drain on performance.
Given the level of information you have given I'm having to guess a bit and can't give a precise answer. However for a definitive understanding of how to optimise UIView performance I recommend checking out this video (though you will need an Apple Developer account to be able to access it):
https://developer.apple.com/videos/wwdc/2011/
Session 121 – Understanding UIKit Rendering
Hope this helps. Paul.
As you can probably tell from my last few questions, I am working on a screen that allows users to edit labels. Pages and all the other lovely apps have glorious resizing handles to show what label is currently being edited.
I am trying to get some feedback on the best way to do this. Is it possible to add an 'dot' image to the centre of all the edges of the label? Is it possible to change the background colour only in sections of a label?
Or should I add an image on top of the label and disable it? The most important feature is for only the uilabel to respond to touches. If I overlay an image, I want it to ignore the touch and hand it off to the label.
Any feedback appreciated!
Cheers Guys!
You will find as many opinions on this as there are programmers. There is not built-in decoration for a view that shows the dot in the middle of each side. But you can add that easily enough. One way is instantiate four instances of an image with the dot and add them as subviews of the view you are decorating. you can then set the center of each dot on the center of each edge in the parent view. As long as clipping is turned off in the parent view, these will show up (if they are not hidden) even if they extend outside the frame of the parent view.
I don't understand what you want to accomplish by changing the background color in sections of the label view, but I this probably has some moderate complexity to it.
You can also to this with core graphics. I'll stop there, though. There are literally many ways to do what you are trying to do.
I am brand new to iPhone app development. I am trying to create an image reader using UIScrollView. I need to focus a portion of an image and hide the rest. Till now I am only able to focus required part of an image but have no clue how to hide the rest. I had a suggestion that, I need to add four views at top, bottom, left and right. I need to hide those as per requirement. But, I was able to go no where with the suggestion. Can you please tell me how can I implement the functionality?
I don't understand what you really want to do. But if you think putting for views above I might suggest you use mask image for the same. Use alpha component.
Atlast I was successful in hiding part of an image. I used four views with background color and resized them according to the portion I need to display.
Right so I got all my lovely openGL stuff working and I can change the background colour via the property of the view or even the window however for the love of god I cant change it to an image.
I have tried adding it to the nib
I have tried adding a UIImageView as
a subview.
I have tried addiing it as a UIColor
with Pattern
I tried making the OpenGL view have a
clear background and setting the
image on the actual window.
Still no joy!
Issue a glClear then render 2 triangles (ie a quad) to the screen with the appropriate image texture mapped onto them.
I have numerous photos in portrait and landscape format. I want to be able to display a "crop" of the photo in a UIImageView on the iphone. If the picture is in landscape format I want it to resize to fit the frame, if it is in portrait format I need it to resize to fit the width, and then be cropped at the top and bottom. As if there is a "window" over the image - so it looks like a landscape picture.
It would be even better if this could be a UIButton - although I am aware that I can use touchesBegan and such on images to make it behave like a button if needs be.
Thanks for any help you can give me.
Thanks
Tom
In an ImageView, you can change the View Mode to Aspect Fill. It will give you the right scaling/cropping you want.
For interactions, you can use a Custom button with no drawing at all (no Title, no Image, no Background) with the same size as your ImageView. That would be safe with regards to the image aspect. I've tried similar stuff using the button's Background or Image properties, it can have some undesired effects (I've ran into a resizing issue on iOS 3.1.3 for instance).
1°) To Crop the Image, try to add a method to UIImage class to do it (you can google it without problem, or even on StackOverFlow)
2°) To add a "window" over your image, just add an UIImageView over your image wich has transparency. It should work ;-)
3°) To know when an image is touched, you can use "touchesBegan" to detect which image were selected. But I think it's the last of your problems ^^
What you cant to achieve isn't so hard, just to it step by step !
If you want more help in one step, say it. But I can't code it all for you ;-)
Good Luck