> 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/layers-ocgs/extract-layer.md).

# Extract layers from PDF on iOS

Learn how to extract PDF layers or OCG (optional content group) from a document with full sample code. Create, extract, and render PDF layers effortlessly. The Apryse iOS SDK streamlines secure docume

To extract PDF layers or OCG (optional content group) from a document.

{% tabs %}
{% tab title="Obj-C" %}
{% code lineNumbers="true" %}

```objc
PTPDFDoc *doc = [[PTPDFDoc alloc] initWithFilepath: filename];
PTPage *page = [doc GetPage: 1];

PTConfig *init_cfg = [doc GetOCGConfig];
PTContext *ctx = [[PTContext alloc] initWithConfig: init_cfg];

PTPDFDraw *pdfdraw = [[PTPDFDraw alloc] initWithDpi: 92];
[pdfdraw SetImageSize: 1000 height: 1000 preserve_aspect_ratio: YES];
[pdfdraw SetOCGContext: ctx]; // Render the page using the given OCG context.

// Disable drawing of content that is not optional (i.e. is not part of any layer).
[ctx SetNonOCDrawing: NO];

// Now render each layer in the input document to a separate image.
PTObj * ocgs = [doc GetOCGs]; // Get the array of all OCGs in the document.
unsigned long i, sz = [ocgs Size];
for (i=0; i<sz; ++i) {
    PTGroup *ocg = [[PTGroup alloc] initWithOcg: [ocgs GetAt: i]];
    [ctx ResetStates: NO];
    [ctx SetState: ocg state: YES];
    NSString* fname = [output_path stringByAppendingFormat: @"pdf_layers_%@.png", [ocg GetName]];
    [pdfdraw  page filename: fname format: @"PNG"];
}

// Now draw content that is not part of any layer...
[ctx SetNonOCDrawing: YES];
[ctx SetOCDrawMode: e_ptNoOC];
[pdfdraw  page filename: [output_path stringByAppendingString: @"pdf_layers_non_oc.png"] format: @"PNG" ];
```

{% endcode %}
{% endtab %}

{% tab title="Swift" %}
{% code lineNumbers="true" %}

```swift
let doc: PTPDFDoc = PTPDFDoc(filepath: filename)
let page: PTPage = doc.getPage(1)

let init_cfg: PTConfig = doc.getOCGConfig()
let ctx: PTContext = PTContext(config: init_cfg)

let pdfdraw: PTPDFDraw = PTPDFDraw(dpi: 92)
pdfdraw.setImageSize(1000, height: 1000, preserve_aspect_ratio: true)
pdfdraw.setOCGContext(ctx)    // Render the page using the given OCG context.

// Disable drawing of content that is not optional (i.e. is not part of any layer).
ctx.setNonOCDrawing(false)

// Now render each layer in the input document to a separate image.
let ocgs: PTObj = doc.getOCGs() {    // Get the array of all OCGs in the document.
var _: UInt = 0
let sz: UInt = ocgs.size()
for i in 0..<sz {
    let ocg: PTGroup = PTGroup(ocg: ocgs.getAt(i))
    ctx.resetStates(false)
    ctx.setState(ocg, state: true)
    let fname: String = output_path + "pdf_layers_\(ocg.getName()).png")
    pdfdraw.export(page, filename: fname, format: "PNG")
}

// Now draw content that is not part of any layer...
ctx.setNonOCDrawing(true)
ctx.setOCDrawMode(e_ptNoOC)
pdfdraw.export(page, filename: output_path + "pdf_layers_non_oc.png", format: "PNG")
```

{% endcode %}
{% endtab %}
{% endtabs %}

[PDF layers (OCG)](/ios/get-started/samples.md#pdflayers) Full sample code which demonstrates how to create, extract, render PDF layers.


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