ImageViewer
/*******************************************************************************
* All Right Reserved. Copyright (c) 1998, 2004 Jackwind Li Guojie
*
* Created on 2004-5-2 14:57:37 by JACK $Id$
*
******************************************************************************/
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Dialog;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.printing.PrintDialog;
import org.eclipse.swt.printing.Printer;
import org.eclipse.swt.printing.PrinterData;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.FileDialog;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.ToolBar;
import org.eclipse.swt.widgets.ToolItem;
public class SWTImageViewer {
Display display = new Display();
Shell shell = new Shell(display);
Canvas canvas;
Image image;
String fileName;
public SWTImageViewer() {
shell.setText("Image viewer");
shell.setLayout(new GridLayout(1, true));
ToolBar toolBar = new ToolBar(shell, SWT.FLAT);
ToolItem itemOpen = new ToolItem(toolBar, SWT.PUSH);
itemOpen.setText("Open");
itemOpen.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event event) {
FileDialog dialog = new FileDialog(shell, SWT.OPEN);
String file = dialog.open();
if (file != null) {
if (image != null)
image.dispose();
image = null;
try {
image = new Image(display, file);
} catch (RuntimeException e) {
// e.printStackTrace();
}
if (image != null) {
fileName = file;
} else {
System.err.println(
"Failed to load image from file: " + file);
}
canvas.redraw();
}
}
});
ToolItem itemPrintPreview = new ToolItem(toolBar, SWT.PUSH);
itemPrintPreview.setText("Preview");
itemPrintPreview.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event event) {
ImagePrintPreviewDialog dialog =
new ImagePrintPreviewDialog(ImageViewer.this);
dialog.open();
}
});
ToolItem itemPrint = new ToolItem(toolBar, SWT.PUSH);
itemPrint.setText("Print");
itemPrint.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event event) {
print();
}
});
canvas = new Canvas(shell, SWT.BORDER);
canvas.setBackground(display.getSystemColor(SWT.COLOR_WHITE));
canvas.setLayoutData(new GridData(GridData.FILL_BOTH));
canvas.addPaintListener(new PaintListener() {
public void paintControl(PaintEvent e) {
if (image == null) {
e.gc.drawString("No image", 0, 0);
} else {
e.gc.drawImage(image, 0, 0);
}
}
});
image = new Image(display, "java2s.gif");
fileName = "scene.jpg";
shell.setSize(500, 400);
shell.open();
//textUser.forceFocus();
// Set up the event loop.
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
// If no more entries in event queue
display.sleep();
}
}
display.dispose();
}
/**
* Lets the user to select a printer and prints the image on it.
*
*/
void print() {
PrintDialog dialog = new PrintDialog(shell);
// Prompts the printer dialog to let the user select a printer.
PrinterData printerData = dialog.open();
if (printerData == null) // the user cancels the dialog
return;
// Loads the printer.
Printer printer = new Printer(printerData);
print(printer, null);
}
/**
* Prints the image current displayed to the specified printer.
*
* @param printer
*/
void print(final Printer printer, PrintMargin printMargin) {
if (image == null) // If no image is loaded, do not print.
return;
final Point printerDPI = printer.getDPI();
final Point displayDPI = display.getDPI();
System.out.println(displayDPI + " " + printerDPI);
final PrintMargin margin = (printMargin == null ? PrintMargin.getPrintMargin(printer, 1.0) : printMargin);
Thread printThread = new Thread() {
public void run() {
if (!printer.startJob(fileName)) {
System.err.println("Failed to start print job!");
printer.dispose();
return;
}
GC gc = new GC(printer);
if (!printer.startPage()) {
System.err.println("Failed to start a new page!");
gc.dispose();
return;
} else {
int imageWidth = image.getBounds().width;
int imageHeight = image.getBounds().height;
// Handles DPI conversion.
double dpiScaleFactorX = printerDPI.x * 1.0 / displayDPI.x;
double dpiScaleFactorY = printerDPI.y * 1.0 / displayDPI.y;
// If the image is too large to draw on a page, reduces its
// width and height proportionally.
double imageSizeFactor =
Math.min(
1,
(margin.right - margin.left)
* 1.0
/ (dpiScaleFactorX * imageWidth));
imageSizeFactor =
Math.min(
imageSizeFactor,
(margin.bottom - margin.top)
* 1.0
/ (dpiScaleFactorY * imageHeight));
// Draws the image to the printer.
gc.drawImage(
image,
0,
0,
imageWidth,
imageHeight,
margin.left,
margin.top,
(int) (dpiScaleFactorX * imageSizeFactor * imageWidth),
(int) (dpiScaleFactorY
* imageSizeFactor
* imageHeight));
gc.dispose();
}
printer.endPage();
printer.endJob();
printer.dispose();
System.out.println("Printing job done!");
}
};
printThread.start();
}
public static void main(String[] args) {
new SWTImageViewer();
}
}
class ImagePrintPreviewDialog extends Dialog {
ImageViewer viewer;
Shell shell;
Canvas canvas;
Printer printer;
PrintMargin margin;
Combo combo;
public ImagePrintPreviewDialog(ImageViewer viewer) {
super(viewer.shell);
this.viewer = viewer;
}
public void open() {
shell =
new Shell(
viewer.shell,
SWT.DIALOG_TRIM | SWT.APPLICATION_MODAL | SWT.RESIZE);
shell.setText("Print preview");
shell.setLayout(new GridLayout(4, false));
final Button buttonSelectPrinter = new Button(shell, SWT.PUSH);
buttonSelectPrinter.setText("Select a printer");
buttonSelectPrinter.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event event) {
PrintDialog dialog = new PrintDialog(shell);
// Prompts the printer dialog to let the user select a printer.
PrinterData printerData = dialog.open();
if (printerData == null) // the user cancels the dialog
return;
// Loads the printer.
final Printer printer = new Printer(printerData);
setPrinter(
printer,
Double.parseDouble(
combo.getItem(combo.getSelectionIndex())));
}
});
new Label(shell, SWT.NULL).setText("Margin in inches: ");
combo = new Combo(shell, SWT.READ_ONLY);
combo.add("0.5");
combo.add("1.0");
combo.add("1.5");
combo.add("2.0");
combo.add("2.5");
combo.add("3.0");
combo.select(1);
combo.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event event) {
double value =
Double.parseDouble(
combo.getItem(combo.getSelectionIndex()));
setPrinter(printer, value);
}
});
final Button buttonPrint = new Button(shell, SWT.PUSH);
buttonPrint.setText("Print");
buttonPrint.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event event) {
if (printer == null)
viewer.print();
else
viewer.print(printer, margin);
shell.dispose();
}
});
canvas = new Canvas(shell, SWT.BORDER);
GridData gridData = new GridData(GridData.FILL_BOTH);
gridData.horizontalSpan = 4;
canvas.setLayoutData(gridData);
canvas.addPaintListener(new PaintListener() {
public void paintControl(PaintEvent e) {
int canvasBorder = 20;
if (printer == null || printer.isDisposed())
return;
Rectangle rectangle = printer.getBounds();
Point canvasSize = canvas.getSize();
double viewScaleFactor =
(canvasSize.x - canvasBorder * 2) * 1.0 / rectangle.width;
viewScaleFactor =
Math.min(
viewScaleFactor,
(canvasSize.y - canvasBorder * 2)
* 1.0
/ rectangle.height);
int offsetX =
(canvasSize.x - (int) (viewScaleFactor * rectangle.width))
/ 2;
int offsetY =
(canvasSize.y - (int) (viewScaleFactor * rectangle.height))
/ 2;
e.gc.setBackground(
shell.getDisplay().getSystemColor(SWT.COLOR_WHITE));
// draws the page layout
e.gc.fillRectangle(
offsetX,
offsetY,
(int) (viewScaleFactor * rectangle.width),
(int) (viewScaleFactor * rectangle.height));
// draws the margin.
e.gc.setLineStyle(SWT.LINE_DASH);
e.gc.setForeground(
shell.getDisplay().getSystemColor(SWT.COLOR_BLACK));
int marginOffsetX =
offsetX + (int) (viewScaleFactor * margin.left);
int marginOffsetY =
offsetY + (int) (viewScaleFactor * margin.top);
e.gc.drawRectangle(
marginOffsetX,
marginOffsetY,
(int) (viewScaleFactor * (margin.right - margin.left)),
(int) (viewScaleFactor * (margin.bottom - margin.top)));
if (viewer.image != null) {
int imageWidth = viewer.image.getBounds().width;
int imageHeight = viewer.image.getBounds().height;
double dpiScaleFactorX =
printer.getDPI().x
* 1.0
/ shell.getDisplay().getDPI().x;
double dpiScaleFactorY =
printer.getDPI().y
* 1.0
/ shell.getDisplay().getDPI().y;
double imageSizeFactor =
Math.min(
1,
(margin.right - margin.left)
* 1.0
/ (dpiScaleFactorX * imageWidth));
imageSizeFactor =
Math.min(
imageSizeFactor,
(margin.bottom - margin.top)
* 1.0
/ (dpiScaleFactorY * imageHeight));
e.gc.drawImage(
viewer.image,
0,
0,
imageWidth,
imageHeight,
marginOffsetX,
marginOffsetY,
(int) (dpiScaleFactorX
* imageSizeFactor
* imageWidth
* viewScaleFactor),
(int) (dpiScaleFactorY
* imageSizeFactor
* imageHeight
* viewScaleFactor));
}
}
});
shell.setSize(400, 400);
shell.open();
setPrinter(null, 1.0);
// Set up the event loop.
while (!shell.isDisposed()) {
if (!shell.getDisplay().readAndDispatch()) {
// If no more entries in event queue
shell.getDisplay().sleep();
}
}
}
/**
* Sets target printer.
*
* @param printer
*/
void setPrinter(Printer printer, double marginSize) {
if (printer == null) {
printer = new Printer(Printer.getDefaultPrinterData());
}
this.printer = printer;
margin = PrintMargin.getPrintMargin(printer, marginSize);
canvas.redraw();
}
}
/**
* Contains margin information (in pixels) for a print job.
*
*/
class PrintMargin {
// Margin to the left side, in pixels
public int left;
// Margins to the right side, in pixels
public int right;
// Margins to the top side, in pixels
public int top;
// Margins to the bottom side, in pixels
public int bottom;
private PrintMargin(int left, int right, int top, int bottom) {
this.left = left;
this.right = right;
this.top = top;
this.bottom = bottom;
}
/**
* Returns a PrintMargin object containing the true border margins for the
* specified printer with the given margin in inches.
* Note: all four sides share the same margin width.
* @param printer
* @param margin
* @return
*/
static PrintMargin getPrintMargin(Printer printer, double margin) {
return getPrintMargin(printer, margin, margin, margin, margin);
}
/**
* Returns a PrintMargin object containing the true border margins for the
* specified printer with the given margin width (in inches) for each side.
*/
static PrintMargin getPrintMargin(
Printer printer,
double marginLeft,
double marginRight,
double marginTop,
double marginBottom) {
Rectangle clientArea = printer.getClientArea();
Rectangle trim = printer.computeTrim(0, 0, 0, 0);
//System.out.println(printer.getBounds() + " - " + clientArea + "" +
// trim);
Point dpi = printer.getDPI();
int leftMargin = (int) (marginLeft * dpi.x) - trim.x;
int rightMargin =
clientArea.width
+ trim.width
- (int) (marginRight * dpi.x)
- trim.x;
int topMargin = (int) (marginTop * dpi.y) - trim.y;
int bottomMargin =
clientArea.height
+ trim.height
- (int) (marginBottom * dpi.y)
- trim.y;
return new PrintMargin(
leftMargin,
rightMargin,
topMargin,
bottomMargin);
}
public String toString() {
return "Margin { "
+ left
+ ", "
+ right
+ "; "
+ top
+ ", "
+ bottom
+ " }";
}
}
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