Add native PDF output support

Currently if one wants to create a PDF file it requires external
libraries and as SWT does not allows an abstraction like Grahics2D in
AWT one can not export real content of SWT components (e.g. Canvas)
except exporting as an raster image or using some hacks.

This now introduce a new PDFDocument to enable direct
PDF generation from SWT widgets via Control.print(GC). This allows
applications to export widget content to PDF files using the standard
GC drawing API as well as even creating completely customized documents.

Author: Copilot

bundles/org.eclipse.swt/Eclipse SWT PI/win32/org/eclipse/swt/internal/win32/OS.java

@@ -337,7 +337,18 @@ public class OS extends C {
 	public static final int DM_COPIES = 0x00000100;
 	public static final int DM_DUPLEX = 0x00001000;
 	public static final int DM_ORIENTATION = 0x00000001;
+	public static final int DM_PAPERSIZE = 0x00000002;
+	public static final int DM_PAPERLENGTH = 0x00000004;
+	public static final int DM_PAPERWIDTH = 0x00000008;
 	public static final int DM_OUT_BUFFER = 2;
+	public static final short DMPAPER_LETTER = 1;
+	public static final short DMPAPER_LEGAL = 5;
+	public static final short DMPAPER_EXECUTIVE = 7;
+	public static final short DMPAPER_A3 = 8;
+	public static final short DMPAPER_A4 = 9;
+	public static final short DMPAPER_A5 = 11;
+	public static final short DMPAPER_TABLOID = 3;
+	public static final short DMPAPER_USER = 256;
 	public static final short DMORIENT_PORTRAIT = 1;
 	public static final short DMORIENT_LANDSCAPE = 2;
 	public static final short DMDUP_SIMPLEX = 1;

bundles/org.eclipse.swt/Eclipse SWT Printing/win32/org/eclipse/swt/printing/PDFDocument.java

@@ -57,6 +57,16 @@ public class PDFDocument implements Drawable {
 	boolean pageStarted = false;
 	String filename;
 
+	/**
+	 * Width of the page in device-independent units
+	 */
+	double width;
+
+	/**
+	 * Height of the page in device-independent units
+	 */
+	double height;
+
 	/**
 	 * Width of the page in points (1/72 inch)
 	 */
@@ -69,6 +79,74 @@ public class PDFDocument implements Drawable {
 
 	/** The name of the Microsoft Print to PDF printer */
 	private static final String PDF_PRINTER_NAME = "Microsoft Print to PDF";
+	
+	/** Helper class to represent a paper size with orientation */
+	private static class PaperSize {
+		int paperSizeConstant;
+		int orientation;
+		double widthInInches;
+		double heightInInches;
+		double wastedArea;
+		
+		PaperSize(int paperSize, int orientation, double width, double height, double wasted) {
+			this.paperSizeConstant = paperSize;
+			this.orientation = orientation;
+			this.widthInInches = width;
+			this.heightInInches = height;
+			this.wastedArea = wasted;
+		}
+	}
+
+	/**
+	 * Finds the best matching standard paper size for the given dimensions.
+	 * Tries both portrait and landscape orientations and selects the one that
+	 * minimizes wasted space while ensuring the content fits.
+	 */
+	private static PaperSize findBestPaperSize(double widthInInches, double heightInInches) {
+		// Common paper sizes (width x height in inches, portrait orientation)
+		int[][] standardSizes = {
+			{OS.DMPAPER_LETTER, 850, 1100},      // 8.5 x 11
+			{OS.DMPAPER_LEGAL, 850, 1400},       // 8.5 x 14
+			{OS.DMPAPER_A4, 827, 1169},          // 8.27 x 11.69
+			{OS.DMPAPER_TABLOID, 1100, 1700},    // 11 x 17
+			{OS.DMPAPER_A3, 1169, 1654},         // 11.69 x 16.54
+			{OS.DMPAPER_EXECUTIVE, 725, 1050},   // 7.25 x 10.5
+			{OS.DMPAPER_A5, 583, 827},           // 5.83 x 8.27
+		};
+		
+		PaperSize bestMatch = null;
+		double minWaste = Double.MAX_VALUE;
+		
+		for (int[] size : standardSizes) {
+			double paperWidth = size[1] / 100.0;
+			double paperHeight = size[2] / 100.0;
+			
+			// Try portrait orientation
+			if (widthInInches <= paperWidth && heightInInches <= paperHeight) {
+				double waste = (paperWidth * paperHeight) - (widthInInches * heightInInches);
+				if (waste < minWaste) {
+					minWaste = waste;
+					bestMatch = new PaperSize(size[0], OS.DMORIENT_PORTRAIT, paperWidth, paperHeight, waste);
+				}
+			}
+			
+			// Try landscape orientation (swap width and height)
+			if (widthInInches <= paperHeight && heightInInches <= paperWidth) {
+				double waste = (paperHeight * paperWidth) - (widthInInches * heightInInches);
+				if (waste < minWaste) {
+					minWaste = waste;
+					bestMatch = new PaperSize(size[0], OS.DMORIENT_LANDSCAPE, paperHeight, paperWidth, waste);
+				}
+			}
+		}
+		
+		// Default to Letter if no match found
+		if (bestMatch == null) {
+			bestMatch = new PaperSize(OS.DMPAPER_LETTER, OS.DMORIENT_PORTRAIT, 8.5, 11.0, 0);
+		}
+		
+		return bestMatch;
+	}
 
 	/**
 	 * Constructs a new PDFDocument with the specified filename and page dimensions.
@@ -77,8 +155,8 @@ public class PDFDocument implements Drawable {
 	 * </p>
 	 *
 	 * @param filename the path to the PDF file to create
-	 * @param widthInPoints the width of each page in points (1/72 inch)
-	 * @param heightInPoints the height of each page in points (1/72 inch)
+	 * @param width the width of each page in device-independent units
+	 * @param height the height of each page in device-independent units
 	 *
 	 * @exception IllegalArgumentException <ul>
 	 *    <li>ERROR_NULL_ARGUMENT - if filename is null</li>
@@ -90,8 +168,8 @@ public class PDFDocument implements Drawable {
 	 *
 	 * @see #dispose()
 	 */
-	public PDFDocument(String filename, double widthInPoints, double heightInPoints) {
-		this(null, filename, widthInPoints, heightInPoints);
+	public PDFDocument(String filename, double width, double height) {
+		this(null, filename, width, height);
 	}
 
 	/**
@@ -103,8 +181,8 @@ public PDFDocument(String filename, double widthInPoints, double heightInPoints)
 	 *
 	 * @param device the device to associate with this PDFDocument
 	 * @param filename the path to the PDF file to create
-	 * @param widthInPoints the width of each page in points (1/72 inch)
-	 * @param heightInPoints the height of each page in points (1/72 inch)
+	 * @param width the width of each page in device-independent units
+	 * @param height the height of each page in device-independent units
 	 *
 	 * @exception IllegalArgumentException <ul>
 	 *    <li>ERROR_NULL_ARGUMENT - if filename is null</li>
@@ -116,13 +194,13 @@ public PDFDocument(String filename, double widthInPoints, double heightInPoints)
 	 *
 	 * @see #dispose()
 	 */
-	public PDFDocument(Device device, String filename, double widthInPoints, double heightInPoints) {
+	public PDFDocument(Device device, String filename, double width, double height) {
 		if (filename == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
-		if (widthInPoints <= 0 || heightInPoints <= 0) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
+		if (width <= 0 || height <= 0) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
 
 		this.filename = filename;
-		this.widthInPoints = widthInPoints;
-		this.heightInPoints = heightInPoints;
+		this.width = width;
+		this.height = height;
 
 		// Get device from the current display if not provided
 		if (device == null) {
@@ -135,6 +213,23 @@ public PDFDocument(Device device, String filename, double widthInPoints, double
 			this.device = device;
 		}
 
+		// Calculate physical size in inches from screen pixels
+		int screenDpiX = 96;
+		int screenDpiY = 96;
+		if (this.device != null) {
+			Point dpi = this.device.getDPI();
+			screenDpiX = dpi.x;
+			screenDpiY = dpi.y;
+		}
+		double widthInInches = width / screenDpiX;
+		double heightInInches = height / screenDpiY;
+		
+		// Microsoft Print to PDF doesn't support custom page sizes
+		// Find the best matching standard paper size
+		PaperSize bestMatch = findBestPaperSize(widthInInches, heightInInches);
+		this.widthInPoints = bestMatch.widthInInches * 72.0;
+		this.heightInPoints = bestMatch.heightInInches * 72.0;
+
 		// Create printer DC for "Microsoft Print to PDF"
 		TCHAR driver = new TCHAR(0, "WINSPOOL", true);
 		TCHAR deviceName = new TCHAR(0, PDF_PRINTER_NAME, true);
@@ -149,6 +244,12 @@ public PDFDocument(Device device, String filename, double widthInPoints, double
 				if (lpInitData != 0) {
 					int rc = OS.DocumentProperties(0, hPrinter[0], deviceName, lpInitData, 0, OS.DM_OUT_BUFFER);
 					if (rc == OS.IDOK) {
+						DEVMODE devmode = new DEVMODE();
+						OS.MoveMemory(devmode, lpInitData, DEVMODE.sizeof);
+						devmode.dmPaperSize = (short) bestMatch.paperSizeConstant;
+						devmode.dmOrientation = (short) bestMatch.orientation;
+						devmode.dmFields = OS.DM_PAPERSIZE | OS.DM_ORIENTATION;
+						OS.MoveMemory(lpInitData, devmode, DEVMODE.sizeof);
 						handle = OS.CreateDC(driver, deviceName, 0, lpInitData);
 					}
 					OS.HeapFree(hHeap, 0, lpInitData);
@@ -322,6 +423,43 @@ public long internal_new_GC(GCData data) {
 				data.font = device.getSystemFont();
 			}
 		}
+		
+		// Set up coordinate system scaling
+		// Get screen DPI
+		int screenDpiX = 96;
+		int screenDpiY = 96;
+		if (device != null) {
+			Point dpi = device.getDPI();
+			screenDpiX = dpi.x;
+			screenDpiY = dpi.y;
+		}
+		
+		// Get PDF printer DPI
+		int pdfDpiX = OS.GetDeviceCaps(handle, OS.LOGPIXELSX);
+		int pdfDpiY = OS.GetDeviceCaps(handle, OS.LOGPIXELSY);
+		
+		// Calculate content size in inches (what user wanted)
+		double contentWidthInInches = width / screenDpiX;
+		double contentHeightInInches = height / screenDpiY;
+		
+		// Calculate scale factor to fit content to page
+		// The page size is the physical paper size we selected
+		double pageWidthInInches = widthInPoints / 72.0;
+		double pageHeightInInches = heightInPoints / 72.0;
+		double scaleToFitWidth = pageWidthInInches / contentWidthInInches;
+		double scaleToFitHeight = pageHeightInInches / contentHeightInInches;
+		
+		// Use the smaller scale to ensure both width and height fit
+		double scaleToFit = Math.min(scaleToFitWidth, scaleToFitHeight);
+		
+		// Combined scale: fit-to-page * DPI conversion
+		float scaleX = (float)(scaleToFit * pdfDpiX / screenDpiX);
+		float scaleY = (float)(scaleToFit * pdfDpiY / screenDpiY);
+		
+		OS.SetGraphicsMode(handle, OS.GM_ADVANCED);
+		float[] transform = new float[] {scaleX, 0, 0, scaleY, 0, 0};
+		OS.SetWorldTransform(handle, transform);
+		
 		isGCCreated = true;
 		return handle;
 	}

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Shell.java

@@ -1350,7 +1350,29 @@ public boolean print (GC gc) {
 	checkWidget ();
 	if (gc == null) error (SWT.ERROR_NULL_ARGUMENT);
 	if (gc.isDisposed ()) error (SWT.ERROR_INVALID_ARGUMENT);
-	return false;
+	// Print only the client area (children) without shell decorations
+	forceResize ();
+	Control [] children = _getChildren ();
+	long gdipGraphics = gc.getGCData().gdipGraphics;
+	for (Control child : children) {
+		Rectangle bounds = child.getBounds();
+		if (gdipGraphics != 0) {
+			// For GDI+, translate the graphics object
+			org.eclipse.swt.internal.gdip.Gdip.Graphics_TranslateTransform(gdipGraphics, bounds.x, bounds.y, org.eclipse.swt.internal.gdip.Gdip.MatrixOrderPrepend);
+			child.print(gc);
+			org.eclipse.swt.internal.gdip.Gdip.Graphics_TranslateTransform(gdipGraphics, -bounds.x, -bounds.y, org.eclipse.swt.internal.gdip.Gdip.MatrixOrderPrepend);
+		} else {
+			// For GDI, modify the world transform to add translation
+			int state = OS.SaveDC(gc.handle);
+			// Create a translation transform matrix
+			float[] translateMatrix = new float[] {1, 0, 0, 1, bounds.x, bounds.y};
+			// Multiply (prepend) the translation to the existing transform
+			OS.ModifyWorldTransform(gc.handle, translateMatrix, OS.MWT_LEFTMULTIPLY);
+			child.print(gc);
+			OS.RestoreDC(gc.handle, state);
+		}
+	}
+	return true;
 }
 
 @Override

examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet388.java

@@ -210,8 +210,8 @@ public static void main(String[] args) {
 				String tempDir = System.getProperty("java.io.tmpdir");
 				String pdfPath = tempDir + "/swt_graphics_demo.pdf";
 
-				Rectangle shellBounds = shell.getBounds();
-				PDFDocument pdf = new PDFDocument(pdfPath, shellBounds.width, shellBounds.height);
+				Rectangle clientArea = shell.getClientArea();
+				PDFDocument pdf = new PDFDocument(pdfPath, clientArea.width, clientArea.height);
 				GC gc = new GC(pdf);
 				shell.print(gc);
 				gc.drawString("Exported to PDF...", 0, 0, true);