package org.eclipse.swt.graphics;
/*
* (c) Copyright IBM Corp. 2000, 2001.
* All Rights Reserved
*/
import org.eclipse.swt.internal.win32.*;
import org.eclipse.swt.*;
/**
* Instances of this class manage operating system resources that
* define how text looks when it is displayed. Fonts may be constructed
* by providing a device and either name, size and style information
* or a <code>FontData</code> object which encapsulates this data.
* <p>
* Application code must explicitly invoke the <code>Font.dispose()</code>
* method to release the operating system resources managed by each instance
* when those instances are no longer required.
* </p>
*
* @see FontData
*/
public final class Font {
/**
* the handle to the OS font resource
* (Warning: This field is platform dependent)
*/
public int handle;
/**
* the device where this font was created
*/
Device device;
/**
* Prevents uninitialized instances from being created outside the package.
*/
Font() {
}
/**
* Constructs a new font given a device and font data
* which describes the desired font's appearance.
* <p>
* You must dispose the font when it is no longer required.
* </p>
*
* @param device the device to create the font on
* @param fd the FontData that describes the desired font (must not be null)
*
* @exception IllegalArgumentException <ul>
* <li>ERROR_NULL_ARGUMENT - if the fd argument is null</li>
* </ul>
* @exception SWTError <ul>
* <li>ERROR_NO_HANDLES - if a font could not be created from the given font data</li>
* </ul>
*/
public Font(Device device, FontData fd) {
if (device == null) device = Device.getDevice();
if (device == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
init(device, fd);
if (device.tracking) device.new_Object(this);
}
/**
* Constructs a new font given a device, a font name,
* the height of the desired font in points, and a font
* style.
* <p>
* You must dispose the font when it is no longer required.
* </p>
*
* @param device the device to create the font on
* @param name the name of the font (must not be null)
* @param height the font height in points
* @param style a bit or combination of NORMAL, BOLD, ITALIC
*
* @exception IllegalArgumentException <ul>
* <li>ERROR_NULL_ARGUMENT - if the name argument is null</li>
* <li>ERROR_INVALID_ARGUMENT - if the height is negative</li>
* </ul>
* @exception SWTError <ul>
* <li>ERROR_NO_HANDLES - if a font could not be created from the given arguments</li>
* </ul>
*/
public Font(Device device, String name, int height, int style) {
if (device == null) device = Device.getDevice();
if (device == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
if (name == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
init(device, new FontData (name, height, style));
if (device.tracking) device.new_Object(this);
}
/**
* Disposes of the operating system resources associated with
* the font. Applications must dispose of all fonts which
* they allocate.
*/
public void dispose() {
if (handle == 0) return;
OS.DeleteObject(handle);
handle = 0;
if (device.tracking) device.dispose_Object(this);
device = null;
}
/**
* Compares the argument to the receiver, and returns true
* if they represent the <em>same</em> object using a class
* specific comparison.
*
* @param object the object to compare with this object
* @return <code>true</code> if the object is the same as this object and <code>false</code> otherwise
*
* @see #hashCode
*/
public boolean equals(Object object) {
if (object == this) return true;
if (!(object instanceof Font)) return false;
Font font = (Font) object;
return device == font.device && handle == font.handle;
}
/**
* Returns an array of <code>FontData</code>s representing the receiver.
* On Windows, only one FontData will be returned per font. On X however,
* a <code>Font</code> object <em>may</em> be composed of multiple X
* fonts. To support this case, we return an array of font data objects.
*
* @return an array of font data objects describing the receiver
*
* @exception SWTException <ul>
* <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
* </ul>
*/
public FontData[] getFontData() {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
LOGFONT logFont = new LOGFONT();
OS.GetObject(handle, LOGFONT.sizeof, logFont);
return new FontData[] {FontData.win32_new(logFont, device.computePoints(logFont))};
}
/**
* Returns an integer hash code for the receiver. Any two
* objects which return <code>true</code> when passed to
* <code>equals</code> must return the same value for this
* method.
*
* @return the receiver's hash
*
* @see #equals
*/
public int hashCode () {
return handle;
}
void init (Device device, FontData fd) {
if (fd == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
this.device = device;
LOGFONT logFont = fd.data;
int lfHeight = logFont.lfHeight;
logFont.lfHeight = device.computePixels(fd.height);
handle = OS.CreateFontIndirect(logFont);
logFont.lfHeight = lfHeight;
if (handle == 0) SWT.error(SWT.ERROR_NO_HANDLES);
}
/**
* Returns <code>true</code> if the font has been disposed,
* and <code>false</code> otherwise.
* <p>
* This method gets the dispose state for the font.
* When a font has been disposed, it is an error to
* invoke any other method using the font.
*
* @return <code>true</code> when the font is disposed and <code>false</code> otherwise
*/
public boolean isDisposed() {
return handle == 0;
}
/**
* Returns a string containing a concise, human-readable
* description of the receiver.
*
* @return a string representation of the receiver
*/
public String toString () {
if (isDisposed()) return "Font {*DISPOSED*}";
return "Font {" + handle + "}";
}
/**
* Invokes platform specific functionality to allocate a new font.
* <p>
* <b>IMPORTANT:</b> This method is <em>not</em> part of the public
* API for <code>Font</code>. 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.
* </p>
*
* @param device the device on which to allocate the color
* @param handle the handle for the font
*
* @private
*/
public static Font win32_new(Device device, int handle) {
if (device == null) device = Device.getDevice();
Font font = new Font();
font.handle = handle;
font.device = device;
return font;
}
}
