Class Printer

  • All Implemented Interfaces:
    Drawable

    public final class Printer
    extends Device
    Instances of this class are used to print to a printer. Applications create a GC on a printer using new GC(printer) and then draw on the printer GC using the usual graphics calls.

    A Printer object may be constructed by providing a PrinterData object which identifies the printer. A PrintDialog presents a print dialog to the user and returns an initialized instance of PrinterData. Alternatively, calling new Printer() will construct a printer object for the user's default printer.

    Application code must explicitly invoke the Printer.dispose() method to release the operating system resources managed by each instance when those instances are no longer required.

    See Also:
    PrinterData, PrintDialog, Printing snippets, Sample code and further information
    • Field Detail

      • handle

        public long handle
        the handle to the printer DC (Warning: This field is platform dependent)

        IMPORTANT: This field is not part of the SWT public API. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms and should never be accessed from application code.

        Restriction:
        This field is not intended to be referenced by clients.
    • Constructor Detail

      • Printer

        public Printer()
        Constructs a new printer representing the default printer.

        Note: You must dispose the printer when it is no longer required.

        Throws:
        SWTError -
        • ERROR_NO_HANDLES - if there is no valid default printer
        See Also:
        Device.dispose()
      • Printer

        public Printer​(PrinterData data)
        Constructs a new printer given a PrinterData object representing the desired printer. If the argument is null, then the default printer will be used.

        Note: You must dispose the printer when it is no longer required.

        Parameters:
        data - the printer data for the specified printer, or null to use the default printer
        Throws:
        IllegalArgumentException -
        • ERROR_INVALID_ARGUMENT - if the specified printer data does not represent a valid printer
        SWTError -
        • ERROR_NO_HANDLES - if there are no valid printers
        See Also:
        Device.dispose()
    • Method Detail

      • getPrinterList

        public static PrinterData[] getPrinterList()
        Returns an array of PrinterData objects representing all available printers. If there are no printers, the array will be empty.
        Returns:
        an array of PrinterData objects representing the available printers
      • getDefaultPrinterData

        public static PrinterData getDefaultPrinterData()
        Returns a PrinterData object representing the default printer or null if there is no default printer.
        Returns:
        the default printer data or null
        Since:
        2.1
      • create

        protected void create​(DeviceData deviceData)
        Creates the printer handle. This method is called internally by the instance creation mechanism of the Device class.
        Overrides:
        create in class Device
        Parameters:
        deviceData - the device data
        See Also:
        Device.init()
      • internal_new_GC

        public long internal_new_GC​(GCData data)
        Invokes platform specific functionality to allocate a new GC handle.

        IMPORTANT: This method is not part of the public API for Printer. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code.

        Specified by:
        internal_new_GC in interface Drawable
        Specified by:
        internal_new_GC in class Device
        Parameters:
        data - the platform specific GC data
        Returns:
        the platform specific GC handle
        Restriction:
        This method is not intended to be referenced by clients.
      • internal_dispose_GC

        public void internal_dispose_GC​(long hDC,
                                        GCData data)
        Invokes platform specific functionality to dispose a GC handle.

        IMPORTANT: This method is not part of the public API for Printer. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code.

        Specified by:
        internal_dispose_GC in interface Drawable
        Specified by:
        internal_dispose_GC in class Device
        Parameters:
        hDC - the platform specific GC handle
        data - the platform specific GC data
        Restriction:
        This method is not intended to be referenced by clients.
      • isAutoScalable

        public boolean isAutoScalable()
        Description copied from interface: Drawable
        Returns true iff coordinates can be auto-scaled on this drawable and false if not. E.g. a GC method should not auto-scale the bounds of a figure drawn on a Printer device, but it may have to auto-scale when drawing on a high-DPI Display monitor.
        Returns:
        true if auto-scaling is enabled for this drawable
        Restriction:
        This method is not intended to be referenced by clients.
      • startJob

        public boolean startJob​(String jobName)
        Starts a print job and returns true if the job started successfully and false otherwise.

        This must be the first method called to initiate a print job, followed by any number of startPage/endPage calls, followed by endJob. Calling startPage, endPage, or endJob before startJob will result in undefined behavior.

        Parameters:
        jobName - the name of the print job to start
        Returns:
        true if the job started successfully and false otherwise.
        Throws:
        SWTException -
        • ERROR_DEVICE_DISPOSED - if the receiver has been disposed
        See Also:
        startPage(), endPage(), endJob()
      • cancelJob

        public void cancelJob()
        Cancels a print job in progress.
        Throws:
        SWTException -
        • ERROR_DEVICE_DISPOSED - if the receiver has been disposed
      • startPage

        public boolean startPage()
        Starts a page and returns true if the page started successfully and false otherwise.

        After calling startJob, this method may be called any number of times along with a matching endPage.

        Returns:
        true if the page started successfully and false otherwise.
        Throws:
        SWTException -
        • ERROR_DEVICE_DISPOSED - if the receiver has been disposed
        See Also:
        endPage(), startJob(java.lang.String), endJob()
      • getDPI

        public Point getDPI()
        Returns a point whose x coordinate is the horizontal dots per inch of the printer, and whose y coordinate is the vertical dots per inch of the printer.
        Overrides:
        getDPI in class Device
        Returns:
        the horizontal and vertical DPI
        Throws:
        SWTException -
        • ERROR_DEVICE_DISPOSED - if the receiver has been disposed
      • getClientArea

        public Rectangle getClientArea()
        Returns a rectangle which describes the area of the receiver which is capable of displaying data.

        For a printer, this is the size of the printable area of the page, in pixels.

        Overrides:
        getClientArea in class Device
        Returns:
        the client area
        Throws:
        SWTException -
        • ERROR_DEVICE_DISPOSED - if the receiver has been disposed
        See Also:
        getBounds(), computeTrim(int, int, int, int)
      • computeTrim

        public Rectangle computeTrim​(int x,
                                     int y,
                                     int width,
                                     int height)
        Given a client area (as described by the arguments), returns a rectangle, relative to the client area's coordinates, that is the client area expanded by the printer's trim (or minimum margins).

        Most printers have a minimum margin on each edge of the paper where the printer device is unable to print. This margin is known as the "trim." This method can be used to calculate the printer's minimum margins by passing in a client area of 0, 0, 0, 0 and then using the resulting x and y coordinates (which will be <= 0) to determine the minimum margins for the top and left edges of the paper, and the resulting width and height (offset by the resulting x and y) to determine the minimum margins for the bottom and right edges of the paper, as follows:

        • The left trim width is -x pixels
        • The top trim height is -y pixels
        • The right trim width is (x + width) pixels
        • The bottom trim height is (y + height) pixels
        Parameters:
        x - the x coordinate of the client area
        y - the y coordinate of the client area
        width - the width of the client area
        height - the height of the client area
        Returns:
        a rectangle, relative to the client area's coordinates, that is the client area expanded by the printer's trim (or minimum margins)
        Throws:
        SWTException -
        • ERROR_DEVICE_DISPOSED - if the receiver has been disposed
        See Also:
        getBounds(), getClientArea()
      • getPrinterData

        public PrinterData getPrinterData()
        Returns a PrinterData object representing the target printer for this print job.
        Returns:
        a PrinterData object describing the receiver
      • checkDevice

        protected void checkDevice()
        Checks the validity of this device.
        Overrides:
        checkDevice in class Device
        Throws:
        SWTException -
        • ERROR_DEVICE_DISPOSED - if the receiver has been disposed
      • release

        protected void release()
        Releases any internal state prior to destroying this printer. This method is called internally by the dispose mechanism of the Device class.
        Overrides:
        release in class Device
        See Also:
        Device.dispose(), Device.destroy()
      • destroy

        protected void destroy()
        Destroys the printer handle. This method is called internally by the dispose mechanism of the Device class.
        Overrides:
        destroy in class Device
        See Also:
        Device.dispose(), Device.release()