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Asked: 2026-06-04T23:56:46+00:00

so i have a uiview that is initialized with a frame that has the

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so i have a uiview that is initialized with a frame that has the height and width that is present for the user, i want the user to be able to draw inside this frame but when the user presses a button, i want the view to cut off that extra wasted space so that the frame is only as big as what the user was drawing. I tried to do something like this 

CGRect boundbox = CGPathGetBoundingBox([myPath CGPath]);
boundbox.origin.x = self.frame.origin.x;
boundbox.origin.y = self.frame.origin.y;
self.frame = boundbox;

However, this does not remove that extra wasted space, it only resizes the view, so that the drawn content looks smaller than previously. What i would like to do instead is to remove
that “whitespace”, i was thinking if it could be possible to scale up the content of the uiview, but im not sure.

To clarify what i mean:

enter image description here

The red border is the area / frame that the user can draw on, the text in the middle is a drawing, when the user presses a button, i want the frame to only encircle the drawing like in figure 2.

enter image description here

Now lets say i have the following scenario, i have drawn a circle on the middle of the screen.

enter image description here

When i then press the button, the scale remains the same but the circle is still in the same position but we have now changed the draw area, so the circle / drawing will look like its cut off like in figure 4.

enter image description here

What i want to do is to move the drawing / bezier path so that it is positioned in the middle of the frame. So that the red area encircles the blue circle.

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1 Answer

  1. Editorial Team

    [EDIT]
    Given your drawings. A UIView will not re-position items in it when you change it’s frame property (or it’s CGRect). In this case you will need to track the items drawn YOURSELF, and then when the button is pressed perform the object translations yourself.

    What that means is you will have to find the object that is left most, the object that is topmost, then move all objects left by that amount, and up by that amount so that all objects are (as a grouping) top-left aligned within the view’s frame. After this you will need to self recognize which object is the right most touching and which object is the bottom most touching.

    NOW, since you have already moved the items left-top, the right most point will define your frame width, and the bottom most point will define your frame height.

    IF YOU SO DESIRE, you should be able to zoom in using the properties below after you have done this.

    [First Answer]
    If I understand your question correctly, you may want to still perform your box frame manipulation, but if you wish to scale you may want to look into the

    contentScaleFactor or
contentStretch

    properties.

    contentScaleFactor should scale both dimensions based upon a singular floating point value (i.e. xWidth * scaleFactor, yHeight * scale factor).

    contentStretch is a CGRect which means that it should scale each dimension (axis) separately.

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