> For the complete documentation index, see [llms.txt](https://docs.apryse.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.apryse.com/ios/ui-customization/adding-a-uiview-to-a-pdf-page.md).
# Add a UIView to a PDF page
Learn how to reposition views in PTPDFViewCtrl when the PDF page shifts due to changes like zooming or presentation mode. Implement delegate methods pdfScrollViewDidEndZooming and onLayoutChanged for
This guide demonstrates how to make a \`UIView\` appear as if it is stuck to a page.
It is convenient for the user to make a `UIView` that is "stuck" to a page record its desired page location. To do this, you could add an extension/category to a `UIView`, or use a derived class, as shown below:
{% tabs %}
{% tab title="C#" %}
{% code lineNumbers="true" %}
```csharp
public class FloatingView : UIView
{
public FloatingView() : base()
{
}
public int PageNumber { get; set; }
public pdftron.PDF.Rect PdfPageRect { get; set; }
}
```
{% endcode %}
{% endtab %}
{% tab title="Swift" %}
{% code lineNumbers="true" %}
```swift
class FloatingView: UIView {
// the page on which the UIView appears
var pageNumber: Int32 = 0
// the location, expressed in PDF coordinates, at which the view appears
var pdfPageRect: PTPDFRect?
}
```
{% endcode %}
{% endtab %}
{% tab title="Obj-C" %}
{% code lineNumbers="true" %}
```objc
@interface FloatingView : UIView
// the page on which the UIView appears
@property (assign, nonatomic) int pageNumber;
// the location, expressed in PDF coordinates, at which the view appears
@property (strong, nonatomic) PTPDFRect* pdfPageRect;
@end
@implementation FloatingView
@end
```
{% endcode %}
{% endtab %}
{% endtabs %}
A red `UIView` positioned near the bottom left hand corner of the first page.
In this example, we will add a red square to a location near the bottom left hand corner of the first page:
{% tabs %}
{% tab title="C#" %}
{% code lineNumbers="true" %}
```csharp
var mCustomView = new FloatingView();
mCustomView.BackgroundColor = UIColor.Red;
mCustomView.PageNumber = 1;
mCustomView.PdfPageRect = new Rect(10, 10, 100, 100);
mPdfViewCtrl.OverlayView.AddSubview(mCustomView);
// position the view
positionFloatingViews();
```
{% endcode %}
{% endtab %}
{% tab title="Swift" %}
{% code lineNumbers="true" %}
```swift
// prepare the new view
let redRect = FloatingView()
redRect.backgroundColor = UIColor.red
redRect.pageNumber = 1
redRect.pdfPageRect = PTPDFRect(x1: 10, y1: 10, x2: 100, y2: 100)
// add the view to PTPDFViewCtrl's overlayView
self.pdfViewCtrl.overlayView.addSubview(redRect)
// position the view
positionFloatingViews()
```
{% endcode %}
{% endtab %}
{% tab title="Obj-C" %}
{% code lineNumbers="true" %}
```objc
// prepare the new view
FloatingView* redRect = [[FloatingView alloc] init];
[redRect setBackgroundColor:[UIColor redColor]];
redRect.pageNumber = 1;
redRect.pdfPageRect = [[PTPDFRect alloc] initWithX1:10 y1:10 x2:100 y2:100];
// add the view to PTPDFViewCtrl's overlayView
[self.pdfViewCtrl.overlayView addSubview:redRect];
// position the view
[self positionFloatingViews];
```
{% endcode %}
{% endtab %}
{% endtabs %}
Without the last line in the code snippet above, the new view would not appear in the correct location. The following method will position it, and any others that have been added:
{% tabs %}
{% tab title="C#" %}
{% code lineNumbers="true" %}
```csharp
void positionFloatingViews()
{
foreach (UIView view in mPdfViewCtrl.OverlayView.Subviews)
{
if (view is FloatingView)
{
var overlayView = view as FloatingView;
bool pageHidden = false;
if (!mPdfViewCtrl.PagePresentationModeIsContinuous)
{
pageHidden = !mPdfViewCtrl.PageIsOnScreen(overlayView.PageNumber);
}
overlayView.Hidden = pageHidden;
CGRect screenRect = mPdfViewCtrl.PDFRectPage2CGRectScreen(TypeConvertHelper.ConvRectToNative(overlayView.PdfPageRect), overlayView.PageNumber);
screenRect.X += (nfloat)mPdfViewCtrl.GetHScrollPos();
screenRect.Y += (nfloat)mPdfViewCtrl.GetVScrollPos();
overlayView.Frame = screenRect;
}
}
}
```
{% endcode %}
{% endtab %}
{% tab title="Swift" %}
{% code lineNumbers="true" %}
```swift
func positionFloatingViews() {
for case let overlayView as FloatingView in self.pdfViewCtrl.overlayView.subviews {
// make sure this is a floating view
if type(of: overlayView) === FloatingView.self {
var pageHidden = false
if !pdfViewCtrl.pagePresentationModeIsContinuous() {
pageHidden = !pdfViewCtrl.pageIs(onScreen: overlayView.pageNumber)
}
overlayView.isHidden = pageHidden
var screenRect: CGRect = pdfViewCtrl.pdfRectPage2CGRectScreen(overlayView.pdfPageRect, pageNumber: overlayView.pageNumber)
screenRect.origin.x += CGFloat(pdfViewCtrl.getHScrollPos())
screenRect.origin.y += CGFloat(pdfViewCtrl.getVScrollPos())
overlayView.frame = screenRect
}
}
}
```
{% endcode %}
{% endtab %}
{% tab title="Obj-C" %}
{% code lineNumbers="true" %}
```objc
-(void)positionFloatingViews
{
for(FloatingView* overlayView in self.pdfViewCtrl.overlayView.subviews)
{
// make sure this is a floating view
if( [overlayView isMemberOfClass:[FloatingView class]])
{
BOOL pageHidden = NO;
if( ![self.pdfViewCtrl pagePresentationModeIsContinuous] )
{
pageHidden = ![self.pdfViewCtrl pageIsOnScreen:overlayView.pageNumber];
}
overlayView.hidden = pageHidden;
CGRect screenRect = [self.pdfViewCtrl PDFRectPage2CGRectScreen:overlayView.pdfPageRect PageNumber:overlayView.pageNumber];
screenRect.origin.x += [self.pdfViewCtrl GetHScrollPos];
screenRect.origin.y += [self.pdfViewCtrl GetVScrollPos];
overlayView.frame = screenRect;
}
}
}
```
{% endcode %}
{% endtab %}
{% endtabs %}
Whenever the PDF page shifts within the [`PTPDFViewCtrl`](https://sdk.apryse.com/api/ios/Classes/PTPDFViewCtrl.html), which may happen when changing the page presentation mode, zooming, and such, the views need to be re-positioned (`positionFloatingViews` needs to run again). To do this, implement the `PTPDFViewCtrl` delegate methods [`pdfScrollViewDidEndZooming:`](https://sdk.apryse.com/api/ios/Protocols/PTPDFViewCtrlDelegate.html#/c:objc\(pl\)PTPDFViewCtrlDelegate\(im\)pdfScrollViewDidZoom:) and [`onLayoutChanged`](https://sdk.apryse.com/api/ios/Protocols/PTPDFViewCtrlDelegate.html#/c:objc\(pl\)PTPDFViewCtrlDelegate\(im\)onLayoutChanged), and in them, call `positionFloatingViews`:
{% tabs %}
{% tab title="C#" %}
{% code lineNumbers="true" %}
```csharp
mPdfViewCtrl.PdfViewCtrlOnLayoutChanged += (sender, e) =>
{
positionFloatingViews();
};
mPdfViewCtrl.PdfScrollViewDidEndZooming += (sender, e) =>
{
positionFloatingViews();
};
```
{% endcode %}
{% endtab %}
{% tab title="Swift" %}
{% code lineNumbers="true" %}
```swift
func pdfViewCtrl(onLayoutChanged pdfViewCtrl: PTPDFViewCtrl!) {
positionFloatingViews()
}
func pdfViewCtrl(_ pdfViewCtrl: PTPDFViewCtrl!, pdfScrollViewDidEndZooming scrollView: UIScrollView!, with view: UIView!, atScale scale: Float) {
positionFloatingViews()
}
```
{% endcode %}
{% endtab %}
{% tab title="Obj-C" %}
{% code lineNumbers="true" %}
```objc
-(void)pdfViewCtrlOnLayoutChanged:(PTPDFViewCtrl *)pdfViewCtrl
{
[self positionFloatingViews];
}
-(void)pdfViewCtrl:(PTPDFViewCtrl *)pdfViewCtrl pdfScrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale
{
[self positionFloatingViews];
}
```
{% endcode %}
{% endtab %}
{% endtabs %}
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