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/DynaPDF/Create PDF with DeviceN Colorspace 2
Required plugins for this example: MBS DynaPDF Plugin
You find this example project in your Plugins Download as a Xojo project file within the examples folder: /DynaPDF/Create PDF with DeviceN Colorspace 2
This example is the version from Fri, 21th Dec 2017.
Project "Create PDF with DeviceN Colorspace 2.xojo_binary_project"
Filetype text
End FileTypes
MenuBar MenuBar1
MenuItem UntitledMenu1 = ""
MenuItem FileMenu = "&File"
MenuItem FileQuit = "Quit"
MenuItem EditMenu = "&Edit"
MenuItem EditUndo = "&Undo"
MenuItem UntitledMenu0 = "-"
MenuItem EditCut = "Cu&t"
MenuItem EditCopy = "&Copy"
MenuItem EditPaste = "&Paste"
MenuItem EditClear = "Clear"
End MenuBar
Class App Inherits Application
EventHandler Sub Open() dim pdf as new MyDynapdfMBS dim f as FolderItem = SpecialFolder.Desktop.Child("Create PDF with DeviceN Colorspace 2.pdf") call pdf.CreateNewPDF f // We simply try this test function here call TestDeviceNColorSpace(pdf) f.launch quit End EventHandler
Sub AddOperator(byref dest as string, value as double, index as integer) // The following function creates the PostScript code to multiply the tint // values with the components of the CMYK color representation. 0 and 1 // color values are optimized to more efficient code. if value = 0.0 then dest = dest + "0 " elseif value = 1.0 then dest = dest + str(index)+" index " else dest = dest + str(index)+" index "+str(value)+" mul " end if End Sub
Sub CreateBlendFunction(byref dest as string, colorants() as double) // Note that this function does not allocate memory. The string must be // long enough to hold the resulting PostScript code. The function can // be used to create the blend function for DeviceN color spaces with up // to 32 color channels. The alternate color space must be DeviceCMYK or // an ICCBased color space whose base color space is in turn DeviceCMYK. // Since the alternate color space must be DeviceCMYK, NumColorants is // always a multiple of 4! dim numColorants as integer = UBound(colorants)+1 dim numColors as integer = numColorants/4 dim index as integer = numColors - 1 dest = "{" // The PostScript code must be enclosed in braces for i as integer = 0 to 3 for j as integer = 0 to NumColorants-1 step 4 // Create code to multiply the tint values with the color values AddOperator(Dest, Colorants(i+j), index) next // Add the resulting components. No range check is required... for j as integer = 0 to numColors - 2 dest = dest + "add " next index = index + 1 next // We are nearly finish. Place the tint values on top of the stack dest = dest + str(index+1)+" 4 roll" // Remove the tint values from the stack for j as integer = 0 to numColors-1 dest = dest + " pop" next dest = dest + "}" // Finish the code with a brace End Sub
Sub TestDeviceNColorSpace(pdf as MyDynaPDFMBS) dim cs as integer dim psFunc as string // Buffer that holds the PostScript code dim cls() as string = array("PANTONE 345 CVC", "PANTONE 293 CVC", "Yellow") dim cls2() as string = array("PANTONE 345 CVC", "PANTONE 293 CVC") dim pcs() as string = array("Cyan", "Magenta", "Yellow", "Black") dim colors() as double = Array(_ // The CMYK color values are taken from Adobe's Photoshop 0.38, 0.00, 0.34, 0.0,_ // Definition of the first spot color 1.00, 0.56, 0.00, 0.0,_ // Definition of the second spot color 0.00, 0.00, 1.00, 0.0_ // Definition of the process color ) call pdf.Append // We need to create the PostScript calculator function first because // it is a required parameter of pdfCreateDeviceNColorSpace(). CreateBlendFunction(psFunc, colors) 'MsgBox psFunc // Create the DeviceN color space cs = pdf.CreateDeviceNColorSpace(cls, psFunc, pdf.kesDeviceCMYK, -1) // cls: The colorants array // psfunc: Our PostScript tint transformation function // kesDeviceCMYK, // Alternate color space // -1: No handle is required for a device color space if (cs < 0) then return // error // We create also Separation color spaces for the spot colors and add // these color spaces as an attribute to the DeviceN color space: dim separations(-1) as integer // First spot color separations.Append pdf.CreateSeparationCS(cls(0), pdf.kesDeviceCMYK, -1, PDF.CMYK(97, 0, 87, 0)) // 0.38 * 255, 0 * 255, 0.34 * 255, 0 * 255 // Second spot color separations.Append pdf.CreateSeparationCS(cls(1), pdf.kesDeviceCMYK, -1, PDF.CMYK(255, 143, 0, 0)) // 1.0 * 255, 0.56 * 255, 0 * 0, 0 * 0 call pdf.AddDeviceNSeparations(cs, cls2, separations) // there we pass only 2 colors! // cs: DeviceN color space handle // cls: Colorants array , // separations: Separation color space handles for these colorants // Because the DeviceN color space uses a process color we add also // the attributes of the process color space to it. Note that all // colorant names must be defined, also if the DeviceN color space // uses only one component of the process color space. call pdf.AddDeviceNProcessColorants(cs, pcs, pdf.kesDeviceCMYK, -1) // cs: DeviceN color space handle // cls: Array of process colorants // kesDeviceCMYK: The used process color space // -1: No handle is required for a device color space // The DeviceN color space is now fully created so that we can use it call pdf.SetExtColorSpace(cs) // Set the DeviceN color space call pdf.SetFillColorEx 150, 100, 100 // Set a fill color // Draw a rectangle with this color call pdf.Rectangle(50.0, 690.0, 200.0, 100.0, pdf.kfmFill) call pdf.EndPage call pdf.CloseFile End Sub
Note "About"
In this example we want to define a DeviceN color space that contains 2 spot colors and the process color yellow. The alternate color space for the spot colors is DeviceCMYK in this example and the process colorant is defined in this color space too. The tint transformation function for such a color space must be able to compute one color from arbitrary combinations of these three colors. So, we need essentially a blend function expressed in PostScript syntax. The definition of a blend function is not difficult but long because the entire code is stack based. However, let us first keep in mind what we need to do. We have already three values on the stack when the function is executed. These are the tint values which were passed to the DeviceN color space. We need to multiply the tint values with the four components of the alternate color representations of all three channels and finally we need to combine these three colors so that we get the resulting output color. This sounds difficult, because a lot of multiplications and additions are required to produce the wished result, but you'll see it's easier as it looks like. The used colors in the DeviceN color space are defined as follows: Colorant name CMYK representation PANTONE 345 CVC (coated) {0.38, 0.00, 0.34, 0.0} or { 97, 0, 87, 0} PANTONE 293 CVC (coated) {1.00, 0.56, 0.00, 0.0} or {255, 143, 0, 0} Yellow {0.00, 0.00, 1.00, 0.0} or { 0, 0, 255, 0} The CMYK color values of the spot colors are taken from the color picker of Adobe's Photoshop. Now, we have all information we need to create the PostScript calculator function. The multiplication of the color channels with the tint values must be done for all three colors included in the color space. Because these are repeating operations we can easily develop a function that creates the necessary code for us:
End Class
Class MyDynaPDFMBS Inherits DynaPDFMBS
EventHandler Function Error(ErrorCode as integer, ErrorMessage as string, ErrorType as integer) As integer // output all messages on the console: System.DebugLog str(ErrorCode)+": "+ErrorMessage // and display dialog: Dim d as New MessageDialog //declare the MessageDialog object Dim b as MessageDialogButton //for handling the result d.icon=MessageDialog.GraphicCaution //display warning icon d.ActionButton.Caption="Continue" d.CancelButton.Visible=True //show the Cancel button // a warning or an error? if BitAnd(ErrorType, me.kE_WARNING) = me.kE_WARNING then // if user decided to ignore, we'll ignore if IgnoreWarnings then Return 0 d.Message="A warning occurred while processing your PDF code." // we add a third button to display all warnings d.AlternateActionButton.Caption = "Ignore warnings" d.AlternateActionButton.Visible = true else d.Message="An error occurred while processing your PDF code." end if d.Explanation = str(ErrorCode)+": "+ErrorMessage b=d.ShowModal //display the dialog Select Case b //determine which button was pressed. Case d.ActionButton Return 0 // ignore Case d.AlternateActionButton IgnoreWarnings = true Return 0 // ignore Case d.CancelButton Return -1 // stop End select End EventHandler
Property IgnoreWarnings As Boolean
End Class
End Project

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