PKDrawing bounds are calculated differently depending on the strokes width, even if visually the drawing would not exceed its container bounds, in fact, when I save and restore it, I get a non expected bounds form it. For example:
There is a PKCanvasView of a size w:330 x h:260.
I save the drawing canvas.drawing.dataRepresentation() , and once I restore it canvas.drawing = try PKDrawing(data: drawData) , I can get drawing bounds as so (x:-24.0, y:-45.0, w:381.0, h:406.0) if I use wide strokes, however the drawing is still perfectly fitted inside the canvas without any spacial scaling done on my side.
Could somebody explain this behaviour, as well as the negative coordinates.
Basically I need to figure out how to get the actual bounds of the drawing regardless its strokes width.
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I want to draw a rectangle on a chart and have it move with the rest of the chart. However, it stays where it was originally rendered in pixel coordinates.
I would have thought there would be a way to add annotations such as this in world coordinates rather than screen coordinates, but I was not able to find a way. Is such a thing possible?
Assuming I am stuck with annotating in screen coordinates, what event(s) do I need to handle to redraw the rectangle when the user zooms or scrolls?
Simple example:
chart.renderer.rect(chart.xAxis[0].toPixels(1432897200000),chart.yAxis[0].toPixels(1.09674),14,14, 0)
http://jsfiddle.net/bz3t79p5/
Also, I have had no luck with using axis.toPixels() for setting the rectangle's width and height. I was getting values that were way out of whack. Is there a trick to converting width and height from world coordinates to pixels?
I have an iPhone 3D model in my SceneKit application, it has a material which I get. It is called iScreen (the image that "is on" the screen of the iPhone):
var iScreen: SCNMaterial!
iScreen = iphone.geometry?.materialWithName("Screen")!
I decided to somehow project a webView there instead of an image.
Therefore I need the frame / position / size of the screen where iScreen "draws" to set the UIWebView's frame. Is that possible?
Note
Of course I tried position, frame, size, etc. but that all was not available :/
you will first have to know to which SCNGeometryElement the material applies (an SCNGeometry is made of one or several SCNGeometryElement).
That geometry element is essentially a list of indices to retrieve vertex data contained in the geometry's SCNGeometrySources. Here you are interested in the position source (it gives you the 3D coordinates of the vertices).
By iterating over these positions you'll be able to find the element's width and height.
I'm working on a educational app involving complex scripts in which I paint parts of different 'letters' different colours. UILabel is out of the question, so I've drilled down into Core Text and am having a surprisingly successful go of painting glyphs in CALayers.
What I haven't managed to do is animate the size of my custom drawn text. Basically I have text on 'tiles' (CALayers) that move around the screen. The moving around is okay, but now I want to zoom in on the ones that users press.
My idea is to try to cache a 'full resolution' tile and then draw it to scale during an animation of an image bounds. So far I've tried to draw and cache and then redraw such a tile in the following way:
UIGraphicsBeginImageContext(CGSizeMake(50, 50));
CGContextRef context = UIGraphicsGetCurrentContext();
//do some drawing...
myTextImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Then in [CALayer drawInContext:(CGContextRef)context],
I call [myTextImage drawAtPoint:CGPointZero].
When I run the app, the console shows <Error>: CGContextDrawImage: invalid context 0x0. Meanwhile I can perfectly while just continue to draw text in context in the same method even after that error is logged.
So I have two questions: (1) Why isn't this working? Should I be using CGBitmap instead?
And more important: (2) Is there a smarter way of solving the overall problem? Maybe storing my text as paths and then somehow getting CAAnimation to draw it at different scales as the bounds of the enclosing CALayer change?
Okay, this is much easier than I thought. Simply draw the text in the drawInContext: of a CALayer inside of a UIView. Then animate the view using the transform property, and the text will shrink or expand as you like.
Just pay attention to scaling so that the text doesn't get blocky. The easiest way to do that is to make sure the transform scale factors do not go above 1. In other words, make the 'default' 1:1 size of your UIView the largest size you ever want to display it.
I have a custom view with some drawing on it.
I want to resize it to a new proportion and I want the pattern I drew in it's drawRect to also be resized by the same proportion.
Is there anyway I can accomplish this without refreshing and redrawing everything.
This should be happening for you automatically with the default contentMode, which is UIViewContentModeScaleToFill. contentMode determines how to adjust the cached bitmap without forcing a new call to drawRect:. Also see contentStretch which allows you to control which part of the view is scaled.
you will have to redraw it for the new proportion.
For that you have to store the points that made the CGPath and scale the points according to the new proportion and render it again.
Redrawing CGPath needs attention.
If you have used simple moveTopoint / AddlinePoint you can do it just by storing points in an array. You can scale and redraw it later.
If you can used functions like addcurveTopoint etc., storing points in array won't work.A general purpose way is needed.For that you have to use the CGpathApply function. You can see an example it here. http://www.mlsite.net/blog/?p=1312
If you need to zoom and no interation neeeded you can take a scrrenshot and and zoom the image.
I'm displaying a PDF page inside a UIScrollView. I started using http://iosguy.com/2010/09/04/presenting-pdf-files-by-yourself/ article as background.
When it comes to zooming I want to do the following thing to avoid blurring results.
When I open the view the zoom scale is 1.0. Now, I want to store somehow the corresponding CGContextRef according to this view which is shown on the whole screen.
Then I always want to scale the corresponding Quartz coordinate system by the zoom scale of the scrollView and finally transform coordinate system to the right place and make the frame larger/smaller corresponding to the scroll view zoom scale.
But I don't know how to save the initial CGContextRef and reload it every time in the drawRect method.
Can somebody help me with that? Or does somebody know how to scale the PDF page properly? Because, when I zoom in or out, the view's frame gets changed and the graphical context always lies within this frame. So I double scale everything (first the frame and then the PDF document within the frame). Hence I need to scale the PDF when the frame covers the whole screen (initial case).
Can somebody help me with that?