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Create PDF file with Spot Colors
I am trying to generate a PDF file with certain components draw with Spot Colours. Spot colours are used for printing and I am not clear on how one would do that but I think that if I can create a custom ColorSpace with a specific name or a color that has a specific name - our printer looks for the name Spot1 and they use the colour green. Can anyone shed any light on how I might be able to do this. For reference I have attached two pdf files with two different spot colours in them. I need to be able to create similar using CGContext and CGPDFDocument. I can already generate the PDF documents using CMYK colors but don't know how I can create the equivalent "spot" colors. At the moment I am loading the page from these attached pdf files and scaling them to fill the page to get a background with the spot color. This works fine but I also need to generate text and lines using this same spot color and I am not clear how I could do that using the Core Graphics APIs. My guess is I need to create a custom ColorSpace with a single color and then use that color for drawing with. The only 'custom' option for creating a ColorSpace seems to be the CGColorSpace(propertyListPList:) constructor, however there does not appear to be any documentation on what needs to be in the property list to do so. Nor can I find any examples of that. Any pointers would be appreciated. Regards
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Dec ’23
Create CGColorSpace from CFPropertyList
I am trying to create a custom CGColorSpace in Swift on macOS but am not sure I really understand the concepts. I want to use a custom color space called Spot1 and if I extract the spot color from a PDF I get the following: "ColorSpace<Dictionary>" = { "Cs2<Array>" = ( Separation, Spot1, DeviceCMYK, { "BitsPerSample<Integer>" = 8; "Domain<Array>" = ( 0, 1 ); "Filter<Name>" = FlateDecode; "FunctionType<Integer>" = 0; "Length<Integer>" = 526; "Range<Array>" = ( 0, 1, 0, 1, 0, 1, 0, 1 ); "Size<Array>" = ( 1024 ); } ); }; How can I create this same color space using the CGColorSpace(propertyListPlist: CFPropertyList) API func createSpot1() -> CGColorSpace? { let dict0 : NSDictionary = [ "BitsPerSample": 8, "Domain" : [0,1], "Filter" : "FlateDecode", "FunctionType" : 0, "Length" : 526, "Range" : [0,1,0,1,0,1,0,1], "Size" : [1024]] let dict : NSDictionary = [ "Cs2" : ["Separation","Spot1", "DeviceCMYK", dict0] ] let space = CGColorSpace(propertyListPlist: dict as CFPropertyList) if space == nil { DebugLog("Spot1 color space is nil!") } return space }
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Dec ’23
How does one create a DataStoreSnapshot for a custom data store ?
The WWDC2024 custom data store example doesn't provide any details on how one would go about creating a DataStoreSnapshot. The example uses a DefaultSnapshot for persisting the data in the DefaultSnapshot format directly in the JSON file. There appears to be no documentation or examples of how one might create a DataStoreSnapshot from data from another database. The Apple documentation for DefaultSnapshot provides no examples of how one might create such a snapshot from data retrieved elsewhere. Can anyone provide a simple example of how one might create such a snapshot from a remote database such that it can be returned as part of the response to a fetch request. For the purpose of this example let's assume I have a CSV file with rows of data and code to read the data from this file. How would I create a snapshot or snapshots for each of the rows of data.
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Oct ’24
Example of creating NSView with custom bindings
Does anyone know where I can find an example of creating a NSView subclass with custom bindings. I need to be able to bind to the object in interface builder. This is the only reference in Apple documents but as is often the case there appear to be no examples. https://developer.apple.com/documentation/objectivec/nsobject/nskeyvaluebindingcreation
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Oct ’24