1 /*
2 * Copyright (c) 1995, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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24 */
25
26 package java.awt.peer;
27
28 import java.awt.AWTEvent;
29 import java.awt.AWTException;
30 import java.awt.BufferCapabilities;
31 import java.awt.Color;
32 import java.awt.Component;
33 import java.awt.Dimension;
34 import java.awt.EventQueue;
35 import java.awt.Font;
36 import java.awt.FontMetrics;
37 import java.awt.Graphics;
38 import java.awt.GraphicsConfiguration;
39 import java.awt.Image;
40 import java.awt.Point;
41 import java.awt.event.FocusEvent.Cause;
42 import java.awt.event.PaintEvent;
43 import java.awt.image.ColorModel;
44 import java.awt.image.VolatileImage;
45
46 import sun.java2d.pipe.Region;
47
48 /**
49 * The peer interface for {@link Component}. This is the top level peer
50 * interface for widgets and defines the bulk of methods for AWT component
51 * peers. Most component peers have to implement this interface (via one
52 * of the subinterfaces), except menu components, which implement
53 * {@link MenuComponentPeer}.
54 *
55 * The peer interfaces are intended only for use in porting
56 * the AWT. They are not intended for use by application
57 * developers, and developers should not implement peers
58 * nor invoke any of the peer methods directly on the peer
59 * instances.
60 */
61 public interface ComponentPeer {
62
63 /**
64 * Operation for {@link #setBounds(int, int, int, int, int)}, indicating
65 * a change in the component location only.
66 *
67 * @see #setBounds(int, int, int, int, int)
68 */
69 public static final int SET_LOCATION = 1;
70
71 /**
72 * Operation for {@link #setBounds(int, int, int, int, int)}, indicating
73 * a change in the component size only.
74 *
75 * @see #setBounds(int, int, int, int, int)
76 */
77 public static final int SET_SIZE = 2;
78
79 /**
80 * Operation for {@link #setBounds(int, int, int, int, int)}, indicating
81 * a change in the component size and location.
82 *
83 * @see #setBounds(int, int, int, int, int)
84 */
85 public static final int SET_BOUNDS = 3;
86
87 /**
88 * Operation for {@link #setBounds(int, int, int, int, int)}, indicating
89 * a change in the component client size. This is used for setting
90 * the 'inside' size of windows, without the border insets.
91 *
92 * @see #setBounds(int, int, int, int, int)
93 */
94 public static final int SET_CLIENT_SIZE = 4;
95
96 /**
97 * Resets the setBounds() operation to DEFAULT_OPERATION. This is not
98 * passed into {@link #setBounds(int, int, int, int, int)}.
99 *
100 * TODO: This is only used internally and should probably be moved outside
101 * the peer interface.
102 *
103 * @see Component#setBoundsOp
104 */
105 public static final int RESET_OPERATION = 5;
106
107 /**
108 * A flag that is used to suppress checks for embedded frames.
109 *
110 * TODO: This is only used internally and should probably be moved outside
111 * the peer interface.
112 */
113 public static final int NO_EMBEDDED_CHECK = (1 << 14);
114
115 /**
116 * The default operation, which is to set size and location.
117 *
118 * TODO: This is only used internally and should probably be moved outside
119 * the peer interface.
120 *
121 * @see Component#setBoundsOp
122 */
123 public static final int DEFAULT_OPERATION = SET_BOUNDS;
124
125 /**
126 * Determines if a component has been obscured, i.e. by an overlapping
127 * window or similar. This is used by JViewport for optimizing performance.
128 * This doesn't have to be implemented, when
129 * {@link #canDetermineObscurity()} returns {@code false}.
130 *
131 * @return {@code true} when the component has been obscured,
132 * {@code false} otherwise
133 *
134 * @see #canDetermineObscurity()
135 * @see javax.swing.JViewport#needsRepaintAfterBlit
136 */
137 boolean isObscured();
138
139 /**
140 * Returns {@code true} when the peer can determine if a component
141 * has been obscured, {@code false} false otherwise.
142 *
143 * @return {@code true} when the peer can determine if a component
144 * has been obscured, {@code false} false otherwise
145 *
146 * @see #isObscured()
147 * @see javax.swing.JViewport#needsRepaintAfterBlit
148 */
149 boolean canDetermineObscurity();
150
151 /**
152 * Makes a component visible or invisible.
153 *
154 * @param v {@code true} to make a component visible,
155 * {@code false} to make it invisible
156 *
157 * @see Component#setVisible(boolean)
158 */
159 void setVisible(boolean v);
160
161 /**
162 * Enables or disables a component. Disabled components are usually grayed
163 * out and cannot be activated.
164 *
165 * @param e {@code true} to enable the component, {@code false}
166 * to disable it
167 *
168 * @see Component#setEnabled(boolean)
169 */
170 void setEnabled(boolean e);
171
172 /**
173 * Paints the component to the specified graphics context. This is called
174 * by {@link Component#paintAll(Graphics)} to paint the component.
175 *
176 * @param g the graphics context to paint to
177 *
178 * @see Component#paintAll(Graphics)
179 */
180 void paint(Graphics g);
181
182 /**
183 * Prints the component to the specified graphics context. This is called
184 * by {@link Component#printAll(Graphics)} to print the component.
185 *
186 * @param g the graphics context to print to
187 *
188 * @see Component#printAll(Graphics)
189 */
190 void print(Graphics g);
191
192 /**
193 * Sets the location or size or both of the component. The location is
194 * specified relative to the component's parent. The {@code op}
195 * parameter specifies which properties change. If it is
196 * {@link #SET_LOCATION}, then only the location changes (and the size
197 * parameters can be ignored). If {@code op} is {@link #SET_SIZE},
198 * then only the size changes (and the location can be ignored). If
199 * {@code op} is {@link #SET_BOUNDS}, then both change. There is a
200 * special value {@link #SET_CLIENT_SIZE}, which is used only for
201 * window-like components to set the size of the client (i.e. the 'inner'
202 * size, without the insets of the window borders).
203 *
204 * @param x the X location of the component
205 * @param y the Y location of the component
206 * @param width the width of the component
207 * @param height the height of the component
208 * @param op the operation flag
209 *
210 * @see #SET_BOUNDS
211 * @see #SET_LOCATION
212 * @see #SET_SIZE
213 * @see #SET_CLIENT_SIZE
214 */
215 void setBounds(int x, int y, int width, int height, int op);
216
217 /**
218 * Called to let the component peer handle events.
219 *
220 * @param e the AWT event to handle
221 *
222 * @see Component#dispatchEvent(AWTEvent)
223 */
224 void handleEvent(AWTEvent e);
225
226 /**
227 * Called to coalesce paint events.
228 *
229 * @param e the paint event to consider to coalesce
230 *
231 * @see EventQueue#coalescePaintEvent
232 */
233 void coalescePaintEvent(PaintEvent e);
234
235 /**
236 * Determines the location of the component on the screen.
237 *
238 * @return the location of the component on the screen
239 *
240 * @see Component#getLocationOnScreen()
241 */
242 Point getLocationOnScreen();
243
244 /**
245 * Determines the preferred size of the component.
246 *
247 * @return the preferred size of the component
248 *
249 * @see Component#getPreferredSize()
250 */
251 Dimension getPreferredSize();
252
253 /**
254 * Determines the minimum size of the component.
255 *
256 * @return the minimum size of the component
257 *
258 * @see Component#getMinimumSize()
259 */
260 Dimension getMinimumSize();
261
262 /**
263 * Returns the color model used by the component.
264 *
265 * @return the color model used by the component
266 *
267 * @see Component#getColorModel()
268 */
269 ColorModel getColorModel();
270
271 /**
272 * Returns a graphics object to paint on the component.
273 *
274 * @return a graphics object to paint on the component
275 *
276 * @see Component#getGraphics()
277 */
278 // TODO: Maybe change this to force Graphics2D, since many things will
279 // break with plain Graphics nowadays.
280 Graphics getGraphics();
281
282 /**
283 * Returns a font metrics object to determine the metrics properties of
284 * the specified font.
285 *
286 * @param font the font to determine the metrics for
287 *
288 * @return a font metrics object to determine the metrics properties of
289 * the specified font
290 *
291 * @see Component#getFontMetrics(Font)
292 */
293 FontMetrics getFontMetrics(Font font);
294
295 /**
296 * Disposes all resources held by the component peer. This is called
297 * when the component has been disconnected from the component hierarchy
298 * and is about to be garbage collected.
299 *
300 * @see Component#removeNotify()
301 */
302 void dispose();
303
304 /**
305 * Sets the foreground color of this component.
306 *
307 * @param c the foreground color to set
308 *
309 * @see Component#setForeground(Color)
310 */
311 void setForeground(Color c);
312
313 /**
314 * Sets the background color of this component.
315 *
316 * @param c the background color to set
317 *
318 * @see Component#setBackground(Color)
319 */
320 void setBackground(Color c);
321
322 /**
323 * Sets the font of this component.
324 *
325 * @param f the font of this component
326 *
327 * @see Component#setFont(Font)
328 */
329 void setFont(Font f);
330
331 /**
332 * Updates the cursor of the component.
333 *
334 * @see Component#updateCursorImmediately
335 */
336 void updateCursorImmediately();
337
338 /**
339 * Requests focus on this component.
340 *
341 * @param lightweightChild the actual lightweight child that requests the
342 * focus
343 * @param temporary {@code true} if the focus change is temporary,
344 * {@code false} otherwise
345 * @param focusedWindowChangeAllowed {@code true} if changing the
346 * focus of the containing window is allowed or not
347 * @param time the time of the focus change request
348 * @param cause the cause of the focus change request
349 *
350 * @return {@code true} if the focus change is guaranteed to be
351 * granted, {@code false} otherwise
352 */
353 boolean requestFocus(Component lightweightChild, boolean temporary,
354 boolean focusedWindowChangeAllowed, long time,
355 Cause cause);
356
357 /**
358 * Returns {@code true} when the component takes part in the focus
359 * traversal, {@code false} otherwise.
360 *
361 * @return {@code true} when the component takes part in the focus
362 * traversal, {@code false} otherwise
363 */
364 boolean isFocusable();
365
366 /**
367 * Creates an empty image with the specified width and height. This is
368 * generally used as a non-accelerated backbuffer for drawing onto the
369 * component (e.g. by Swing).
370 *
371 * @param width the width of the image
372 * @param height the height of the image
373 *
374 * @return the created image
375 *
376 * @see Component#createImage(int, int)
377 */
378 // TODO: Maybe make that return a BufferedImage, because some stuff will
379 // break if a different kind of image is returned.
380 Image createImage(int width, int height);
381
382 /**
383 * Creates an empty volatile image with the specified width and height.
384 * This is generally used as an accelerated backbuffer for drawing onto
385 * the component (e.g. by Swing).
386 *
387 * @param width the width of the image
388 * @param height the height of the image
389 *
390 * @return the created volatile image
391 *
392 * @see Component#createVolatileImage(int, int)
393 */
394 // TODO: Include capabilities here and fix Component#createVolatileImage
395 VolatileImage createVolatileImage(int width, int height);
396
397 /**
398 * Returns the graphics configuration that corresponds to this component.
399 *
400 * @return the graphics configuration that corresponds to this component
401 *
402 * @see Component#getGraphicsConfiguration()
403 */
404 GraphicsConfiguration getGraphicsConfiguration();
405
406 /**
407 * Determines if the component handles wheel scrolling itself. Otherwise
408 * it is delegated to the component's parent.
409 *
410 * @return {@code true} if the component handles wheel scrolling,
411 * {@code false} otherwise
412 *
413 * @see Component#dispatchEventImpl(AWTEvent)
414 */
415 boolean handlesWheelScrolling();
416
417 /**
418 * Create {@code numBuffers} flipping buffers with the specified
419 * buffer capabilities.
420 *
421 * @param numBuffers the number of buffers to create
422 * @param caps the buffer capabilities
423 *
424 * @throws AWTException if flip buffering is not supported
425 */
426 void createBuffers(int numBuffers, BufferCapabilities caps)
427 throws AWTException;
428
429 /**
430 * Returns the back buffer as image.
431 *
432 * @return the back buffer as image
433 */
434 Image getBackBuffer();
435
436 /**
437 * Move the back buffer to the front buffer.
438 *
439 * @param x1 the area to be flipped, upper left X coordinate
440 * @param y1 the area to be flipped, upper left Y coordinate
441 * @param x2 the area to be flipped, lower right X coordinate
442 * @param y2 the area to be flipped, lower right Y coordinate
443 * @param flipAction the flip action to perform
444 */
445 void flip(int x1, int y1, int x2, int y2, BufferCapabilities.FlipContents flipAction);
446
447 /**
448 * Destroys all created buffers.
449 */
450 void destroyBuffers();
451
452 /**
453 * Reparents this peer to the new parent referenced by
454 * {@code newContainer} peer. Implementation depends on toolkit and
455 * container.
456 *
457 * @param newContainer peer of the new parent container
458 *
459 * @since 1.5
460 */
461 void reparent(ContainerPeer newContainer);
462
463 /**
464 * Returns whether this peer supports reparenting to another parent without
465 * destroying the peer.
466 *
467 * @return true if appropriate reparent is supported, false otherwise
468 *
469 * @since 1.5
470 */
471 boolean isReparentSupported();
472
473 /**
474 * Used by lightweight implementations to tell a ComponentPeer to layout
475 * its sub-elements. For instance, a lightweight Checkbox needs to layout
476 * the box, as well as the text label.
477 *
478 * @see Component#validate()
479 */
480 void layout();
481
482 /**
483 * Applies the shape to the native component window.
484 * @param shape the shape to apply
485 * @since 1.7
486 *
487 * @see Component#applyCompoundShape
488 */
489 void applyShape(Region shape);
490
491 /**
492 * Lowers this component at the bottom of the above HW peer. If the above parameter
493 * is null then the method places this component at the top of the Z-order.
494 * @param above the peer to lower this component with respect to
495 */
496 void setZOrder(ComponentPeer above);
497
498 /**
499 * Updates internal data structures related to the component's GC.
500 * @param gc the reference graphics configuration
501 * @return if the peer needs to be recreated for the changes to take effect
502 * @since 1.7
503 */
504 boolean updateGraphicsData(GraphicsConfiguration gc);
505 }