1 /*
2 * Copyright (c) 2003, 2015, 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
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package sun.java2d.opengl;
27
28 import java.awt.AlphaComposite;
29 import java.awt.Composite;
30 import java.awt.GraphicsEnvironment;
31 import java.awt.Rectangle;
32 import java.awt.Transparency;
33 import java.awt.image.ColorModel;
34 import java.awt.image.Raster;
35 import sun.awt.SunHints;
36 import sun.awt.image.PixelConverter;
37 import sun.java2d.pipe.hw.AccelSurface;
38 import sun.java2d.SunGraphics2D;
39 import sun.java2d.SurfaceData;
40 import sun.java2d.SurfaceDataProxy;
41 import sun.java2d.loops.CompositeType;
42 import sun.java2d.loops.GraphicsPrimitive;
43 import sun.java2d.loops.MaskFill;
44 import sun.java2d.loops.SurfaceType;
45 import sun.java2d.pipe.ParallelogramPipe;
46 import sun.java2d.pipe.PixelToParallelogramConverter;
47 import sun.java2d.pipe.RenderBuffer;
48 import sun.java2d.pipe.TextPipe;
49 import static sun.java2d.pipe.BufferedOpCodes.*;
50 import static sun.java2d.opengl.OGLContext.OGLContextCaps.*;
51
52 /**
53 * This class describes an OpenGL "surface", that is, a region of pixels
54 * managed via OpenGL. An OGLSurfaceData can be tagged with one of three
55 * different SurfaceType objects for the purpose of registering loops, etc.
56 * This diagram shows the hierarchy of OGL SurfaceTypes:
57 *
58 * Any
59 * / \
60 * OpenGLSurface OpenGLTexture
61 * |
62 * OpenGLSurfaceRTT
63 *
64 * OpenGLSurface
65 * This kind of surface can be rendered to using OpenGL APIs. It is also
66 * possible to copy an OpenGLSurface to another OpenGLSurface (or to itself).
67 * This is typically accomplished by calling MakeContextCurrent(dstSD, srcSD)
68 * and then calling glCopyPixels() (although there are other techniques to
69 * achieve the same goal).
70 *
71 * OpenGLTexture
72 * This kind of surface cannot be rendered to using OpenGL (in the same sense
73 * as in OpenGLSurface). However, it is possible to upload a region of pixels
74 * to an OpenGLTexture object via glTexSubImage2D(). One can also copy a
75 * surface of type OpenGLTexture to an OpenGLSurface by binding the texture
76 * to a quad and then rendering it to the destination surface (this process
77 * is known as "texture mapping").
78 *
79 * OpenGLSurfaceRTT
80 * This kind of surface can be thought of as a sort of hybrid between
81 * OpenGLSurface and OpenGLTexture, in that one can render to this kind of
82 * surface as if it were of type OpenGLSurface, but the process of copying
83 * this kind of surface to another is more like an OpenGLTexture. (Note that
84 * "RTT" stands for "render-to-texture".)
85 *
86 * In addition to these SurfaceType variants, we have also defined some
87 * constants that describe in more detail the type of underlying OpenGL
88 * surface. This table helps explain the relationships between those
89 * "type" constants and their corresponding SurfaceType:
90 *
91 * OGL Type Corresponding SurfaceType
92 * -------- -------------------------
93 * WINDOW OpenGLSurface
94 * TEXTURE OpenGLTexture
95 * FLIP_BACKBUFFER OpenGLSurface
96 * FBOBJECT OpenGLSurfaceRTT
97 */
98 public abstract class OGLSurfaceData extends SurfaceData
99 implements AccelSurface {
100
101 /**
102 * OGL-specific surface types
103 *
104 * @see sun.java2d.pipe.hw.AccelSurface
105 */
106 public static final int FBOBJECT = RT_TEXTURE;
107
108 /**
109 * Pixel formats
110 */
111 public static final int PF_INT_ARGB = 0;
112 public static final int PF_INT_ARGB_PRE = 1;
113 public static final int PF_INT_RGB = 2;
114 public static final int PF_INT_RGBX = 3;
115 public static final int PF_INT_BGR = 4;
116 public static final int PF_INT_BGRX = 5;
117 public static final int PF_USHORT_565_RGB = 6;
118 public static final int PF_USHORT_555_RGB = 7;
119 public static final int PF_USHORT_555_RGBX = 8;
120 public static final int PF_BYTE_GRAY = 9;
121 public static final int PF_USHORT_GRAY = 10;
122 public static final int PF_3BYTE_BGR = 11;
123
124 /**
125 * SurfaceTypes
126 */
127 private static final String DESC_OPENGL_SURFACE = "OpenGL Surface";
128 private static final String DESC_OPENGL_SURFACE_RTT =
129 "OpenGL Surface (render-to-texture)";
130 private static final String DESC_OPENGL_TEXTURE = "OpenGL Texture";
131
132 static final SurfaceType OpenGLSurface =
133 SurfaceType.Any.deriveSubType(DESC_OPENGL_SURFACE,
134 PixelConverter.ArgbPre.instance);
135 static final SurfaceType OpenGLSurfaceRTT =
136 OpenGLSurface.deriveSubType(DESC_OPENGL_SURFACE_RTT);
137 static final SurfaceType OpenGLTexture =
138 SurfaceType.Any.deriveSubType(DESC_OPENGL_TEXTURE);
139
140 /** This will be true if the fbobject system property has been enabled. */
141 private static boolean isFBObjectEnabled;
142
143 /** This will be true if the lcdshader system property has been enabled.*/
144 private static boolean isLCDShaderEnabled;
145
146 /** This will be true if the biopshader system property has been enabled.*/
147 private static boolean isBIOpShaderEnabled;
148
149 /** This will be true if the gradshader system property has been enabled.*/
150 private static boolean isGradShaderEnabled;
151
152 private OGLGraphicsConfig graphicsConfig;
153 protected int type;
154 // these fields are set from the native code when the surface is
155 // initialized
156 private int nativeWidth, nativeHeight;
157
158 protected static OGLRenderer oglRenderPipe;
159 protected static PixelToParallelogramConverter oglTxRenderPipe;
160 protected static ParallelogramPipe oglAAPgramPipe;
161 protected static OGLTextRenderer oglTextPipe;
162 protected static OGLDrawImage oglImagePipe;
163
164 protected native boolean initTexture(long pData,
165 boolean isOpaque, boolean texNonPow2,
166 boolean texRect,
167 int width, int height);
168 protected native boolean initFBObject(long pData,
169 boolean isOpaque, boolean texNonPow2,
170 boolean texRect,
171 int width, int height);
172 protected native boolean initFlipBackbuffer(long pData);
173
174 private native int getTextureTarget(long pData);
175 private native int getTextureID(long pData);
176
177 static {
178 if (!GraphicsEnvironment.isHeadless()) {
179 // fbobject currently enabled by default; use "false" to disable
180 String fbo = java.security.AccessController.doPrivileged(
181 new sun.security.action.GetPropertyAction(
182 "sun.java2d.opengl.fbobject"));
183 isFBObjectEnabled = !"false".equals(fbo);
184
185 // lcdshader currently enabled by default; use "false" to disable
186 String lcd = java.security.AccessController.doPrivileged(
187 new sun.security.action.GetPropertyAction(
188 "sun.java2d.opengl.lcdshader"));
189 isLCDShaderEnabled = !"false".equals(lcd);
190
191 // biopshader currently enabled by default; use "false" to disable
192 String biop = java.security.AccessController.doPrivileged(
193 new sun.security.action.GetPropertyAction(
194 "sun.java2d.opengl.biopshader"));
195 isBIOpShaderEnabled = !"false".equals(biop);
196
197 // gradshader currently enabled by default; use "false" to disable
198 String grad = java.security.AccessController.doPrivileged(
199 new sun.security.action.GetPropertyAction(
200 "sun.java2d.opengl.gradshader"));
201 isGradShaderEnabled = !"false".equals(grad);
202
203 OGLRenderQueue rq = OGLRenderQueue.getInstance();
204 oglImagePipe = new OGLDrawImage();
205 oglTextPipe = new OGLTextRenderer(rq);
206 oglRenderPipe = new OGLRenderer(rq);
207 if (GraphicsPrimitive.tracingEnabled()) {
208 oglTextPipe = oglTextPipe.traceWrap();
209 //The wrapped oglRenderPipe will wrap the AA pipe as well...
210 //oglAAPgramPipe = oglRenderPipe.traceWrap();
211 }
212 oglAAPgramPipe = oglRenderPipe.getAAParallelogramPipe();
213 oglTxRenderPipe =
214 new PixelToParallelogramConverter(oglRenderPipe,
215 oglRenderPipe,
216 1.0, 0.25, true);
217
218 OGLBlitLoops.register();
219 OGLMaskFill.register();
220 OGLMaskBlit.register();
221 }
222 }
223
224 protected OGLSurfaceData(OGLGraphicsConfig gc,
225 ColorModel cm, int type)
226 {
227 super(getCustomSurfaceType(type), cm);
228 this.graphicsConfig = gc;
229 this.type = type;
230 setBlitProxyKey(gc.getProxyKey());
231 }
232
233 @Override
234 public SurfaceDataProxy makeProxyFor(SurfaceData srcData) {
235 return OGLSurfaceDataProxy.createProxy(srcData, graphicsConfig);
236 }
237
238 /**
239 * Returns the appropriate SurfaceType corresponding to the given OpenGL
240 * surface type constant (e.g. TEXTURE -> OpenGLTexture).
241 */
242 private static SurfaceType getCustomSurfaceType(int oglType) {
243 switch (oglType) {
244 case TEXTURE:
245 return OpenGLTexture;
246 case FBOBJECT:
247 return OpenGLSurfaceRTT;
248 default:
249 return OpenGLSurface;
250 }
251 }
252
253 /**
254 * Note: This should only be called from the QFT under the AWT lock.
255 * This method is kept separate from the initSurface() method below just
256 * to keep the code a bit cleaner.
257 */
258 private void initSurfaceNow(int width, int height) {
259 boolean isOpaque = (getTransparency() == Transparency.OPAQUE);
260 boolean success = false;
261
262 switch (type) {
263 case TEXTURE:
264 success = initTexture(getNativeOps(),
265 isOpaque, isTexNonPow2Available(),
266 isTexRectAvailable(),
267 width, height);
268 break;
269
270 case FBOBJECT:
271 success = initFBObject(getNativeOps(),
272 isOpaque, isTexNonPow2Available(),
273 isTexRectAvailable(),
274 width, height);
275 break;
276
277 case FLIP_BACKBUFFER:
278 success = initFlipBackbuffer(getNativeOps());
279 break;
280
281 default:
282 break;
283 }
284
285 if (!success) {
286 throw new OutOfMemoryError("can't create offscreen surface");
287 }
288 }
289
290 /**
291 * Initializes the appropriate OpenGL offscreen surface based on the value
292 * of the type parameter. If the surface creation fails for any reason,
293 * an OutOfMemoryError will be thrown.
294 */
295 protected void initSurface(final int width, final int height) {
296 OGLRenderQueue rq = OGLRenderQueue.getInstance();
297 rq.lock();
298 try {
299 switch (type) {
300 case TEXTURE:
301 case FBOBJECT:
302 // need to make sure the context is current before
303 // creating the texture or fbobject
304 OGLContext.setScratchSurface(graphicsConfig);
305 break;
306 default:
307 break;
308 }
309 rq.flushAndInvokeNow(new Runnable() {
310 public void run() {
311 initSurfaceNow(width, height);
312 }
313 });
314 } finally {
315 rq.unlock();
316 }
317 }
318
319 /**
320 * Returns the OGLContext for the GraphicsConfig associated with this
321 * surface.
322 */
323 public final OGLContext getContext() {
324 return graphicsConfig.getContext();
325 }
326
327 /**
328 * Returns the OGLGraphicsConfig associated with this surface.
329 */
330 final OGLGraphicsConfig getOGLGraphicsConfig() {
331 return graphicsConfig;
332 }
333
334 /**
335 * Returns one of the surface type constants defined above.
336 */
337 public final int getType() {
338 return type;
339 }
340
341 /**
342 * If this surface is backed by a texture object, returns the target
343 * for that texture (either GL_TEXTURE_2D or GL_TEXTURE_RECTANGLE_ARB).
344 * Otherwise, this method will return zero.
345 */
346 public final int getTextureTarget() {
347 return getTextureTarget(getNativeOps());
348 }
349
350 /**
351 * If this surface is backed by a texture object, returns the texture ID
352 * for that texture.
353 * Otherwise, this method will return zero.
354 */
355 public final int getTextureID() {
356 return getTextureID(getNativeOps());
357 }
358
359 /**
360 * Returns native resource of specified {@code resType} associated with
361 * this surface.
362 *
363 * Specifically, for {@code OGLSurfaceData} this method returns the
364 * the following:
365 * <pre>
366 * TEXTURE - texture id
367 * </pre>
368 *
369 * Note: the resource returned by this method is only valid on the rendering
370 * thread.
371 *
372 * @return native resource of specified type or 0L if
373 * such resource doesn't exist or can not be retrieved.
374 * @see sun.java2d.pipe.hw.AccelSurface#getNativeResource
375 */
376 public long getNativeResource(int resType) {
377 if (resType == TEXTURE) {
378 return getTextureID();
379 }
380 return 0L;
381 }
382
383 public Raster getRaster(int x, int y, int w, int h) {
384 throw new InternalError("not implemented yet");
385 }
386
387 /**
388 * For now, we can only render LCD text if:
389 * - the fragment shader extension is available, and
390 * - the source color is opaque, and
391 * - blending is SrcOverNoEa or disabled
392 * - and the destination is opaque
393 *
394 * Eventually, we could enhance the native OGL text rendering code
395 * and remove the above restrictions, but that would require significantly
396 * more code just to support a few uncommon cases.
397 */
398 public boolean canRenderLCDText(SunGraphics2D sg2d) {
399 return
400 graphicsConfig.isCapPresent(CAPS_EXT_LCD_SHADER) &&
401 sg2d.surfaceData.getTransparency() == Transparency.OPAQUE &&
402 sg2d.paintState <= SunGraphics2D.PAINT_OPAQUECOLOR &&
403 (sg2d.compositeState <= SunGraphics2D.COMP_ISCOPY ||
404 (sg2d.compositeState <= SunGraphics2D.COMP_ALPHA && canHandleComposite(sg2d.composite)));
405 }
406
407 private boolean canHandleComposite(Composite c) {
408 if (c instanceof AlphaComposite) {
409 AlphaComposite ac = (AlphaComposite)c;
410
411 return ac.getRule() == AlphaComposite.SRC_OVER && ac.getAlpha() >= 1f;
412 }
413 return false;
414 }
415
416 public void validatePipe(SunGraphics2D sg2d) {
417 TextPipe textpipe;
418 boolean validated = false;
419
420 // OGLTextRenderer handles both AA and non-AA text, but
421 // only works with the following modes:
422 // (Note: For LCD text we only enter this code path if
423 // canRenderLCDText() has already validated that the mode is
424 // CompositeType.SrcNoEa (opaque color), which will be subsumed
425 // by the CompositeType.SrcNoEa (any color) test below.)
426
427 if (/* CompositeType.SrcNoEa (any color) */
428 (sg2d.compositeState <= SunGraphics2D.COMP_ISCOPY &&
429 sg2d.paintState <= SunGraphics2D.PAINT_ALPHACOLOR) ||
430
431 /* CompositeType.SrcOver (any color) */
432 (sg2d.compositeState == SunGraphics2D.COMP_ALPHA &&
433 sg2d.paintState <= SunGraphics2D.PAINT_ALPHACOLOR &&
434 (((AlphaComposite)sg2d.composite).getRule() ==
435 AlphaComposite.SRC_OVER)) ||
436
437 /* CompositeType.Xor (any color) */
438 (sg2d.compositeState == SunGraphics2D.COMP_XOR &&
439 sg2d.paintState <= SunGraphics2D.PAINT_ALPHACOLOR))
440 {
441 textpipe = oglTextPipe;
442 } else {
443 // do this to initialize textpipe correctly; we will attempt
444 // to override the non-text pipes below
445 super.validatePipe(sg2d);
446 textpipe = sg2d.textpipe;
447 validated = true;
448 }
449
450 PixelToParallelogramConverter txPipe = null;
451 OGLRenderer nonTxPipe = null;
452
453 if (sg2d.antialiasHint != SunHints.INTVAL_ANTIALIAS_ON) {
454 if (sg2d.paintState <= SunGraphics2D.PAINT_ALPHACOLOR) {
455 if (sg2d.compositeState <= SunGraphics2D.COMP_XOR) {
456 txPipe = oglTxRenderPipe;
457 nonTxPipe = oglRenderPipe;
458 }
459 } else if (sg2d.compositeState <= SunGraphics2D.COMP_ALPHA) {
460 if (OGLPaints.isValid(sg2d)) {
461 txPipe = oglTxRenderPipe;
462 nonTxPipe = oglRenderPipe;
463 }
464 // custom paints handled by super.validatePipe() below
465 }
466 } else {
467 if (sg2d.paintState <= SunGraphics2D.PAINT_ALPHACOLOR) {
468 if (graphicsConfig.isCapPresent(CAPS_PS30) &&
469 (sg2d.imageComp == CompositeType.SrcOverNoEa ||
470 sg2d.imageComp == CompositeType.SrcOver))
471 {
472 if (!validated) {
473 super.validatePipe(sg2d);
474 validated = true;
475 }
476 PixelToParallelogramConverter aaConverter =
477 new PixelToParallelogramConverter(sg2d.shapepipe,
478 oglAAPgramPipe,
479 1.0/8.0, 0.499,
480 false);
481 sg2d.drawpipe = aaConverter;
482 sg2d.fillpipe = aaConverter;
483 sg2d.shapepipe = aaConverter;
484 } else if (sg2d.compositeState == SunGraphics2D.COMP_XOR) {
485 // install the solid pipes when AA and XOR are both enabled
486 txPipe = oglTxRenderPipe;
487 nonTxPipe = oglRenderPipe;
488 }
489 }
490 // other cases handled by super.validatePipe() below
491 }
492
493 if (txPipe != null) {
494 if (sg2d.transformState >= SunGraphics2D.TRANSFORM_TRANSLATESCALE) {
495 sg2d.drawpipe = txPipe;
496 sg2d.fillpipe = txPipe;
497 } else if (sg2d.strokeState != SunGraphics2D.STROKE_THIN) {
498 sg2d.drawpipe = txPipe;
499 sg2d.fillpipe = nonTxPipe;
500 } else {
501 sg2d.drawpipe = nonTxPipe;
502 sg2d.fillpipe = nonTxPipe;
503 }
504 // Note that we use the transforming pipe here because it
505 // will examine the shape and possibly perform an optimized
506 // operation if it can be simplified. The simplifications
507 // will be valid for all STROKE and TRANSFORM types.
508 sg2d.shapepipe = txPipe;
509 } else {
510 if (!validated) {
511 super.validatePipe(sg2d);
512 }
513 }
514
515 // install the text pipe based on our earlier decision
516 sg2d.textpipe = textpipe;
517
518 // always override the image pipe with the specialized OGL pipe
519 sg2d.imagepipe = oglImagePipe;
520 }
521
522 @Override
523 protected MaskFill getMaskFill(SunGraphics2D sg2d) {
524 if (sg2d.paintState > SunGraphics2D.PAINT_ALPHACOLOR) {
525 /*
526 * We can only accelerate non-Color MaskFill operations if
527 * all of the following conditions hold true:
528 * - there is an implementation for the given paintState
529 * - the current Paint can be accelerated for this destination
530 * - multitexturing is available (since we need to modulate
531 * the alpha mask texture with the paint texture)
532 *
533 * In all other cases, we return null, in which case the
534 * validation code will choose a more general software-based loop.
535 */
536 if (!OGLPaints.isValid(sg2d) ||
537 !graphicsConfig.isCapPresent(CAPS_MULTITEXTURE))
538 {
539 return null;
540 }
541 }
542 return super.getMaskFill(sg2d);
543 }
544
545 @Override
546 public boolean copyArea(SunGraphics2D sg2d, int x, int y, int w, int h,
547 int dx, int dy) {
548 final int state = sg2d.transformState;
549 if (state > SunGraphics2D.TRANSFORM_TRANSLATESCALE
550 || sg2d.compositeState >= SunGraphics2D.COMP_XOR) {
551 return false;
552 }
553 oglRenderPipe.copyArea(sg2d, x, y, w, h, dx, dy);
554 return true;
555 }
556
557 public void flush() {
558 invalidate();
559 OGLRenderQueue rq = OGLRenderQueue.getInstance();
560 rq.lock();
561 try {
562 // make sure we have a current context before
563 // disposing the native resources (e.g. texture object)
564 OGLContext.setScratchSurface(graphicsConfig);
565
566 RenderBuffer buf = rq.getBuffer();
567 rq.ensureCapacityAndAlignment(12, 4);
568 buf.putInt(FLUSH_SURFACE);
569 buf.putLong(getNativeOps());
570
571 // this call is expected to complete synchronously, so flush now
572 rq.flushNow();
573 } finally {
574 rq.unlock();
575 }
576 }
577
578 /**
579 * Disposes the native resources associated with the given OGLSurfaceData
580 * (referenced by the pData parameter). This method is invoked from
581 * the native Dispose() method from the Disposer thread when the
582 * Java-level OGLSurfaceData object is about to go away. Note that we
583 * also pass a reference to the native GLX/WGLGraphicsConfigInfo
584 * (pConfigInfo) for the purposes of making a context current.
585 */
586 static void dispose(long pData, long pConfigInfo) {
587 OGLRenderQueue rq = OGLRenderQueue.getInstance();
588 rq.lock();
589 try {
590 // make sure we have a current context before
591 // disposing the native resources (e.g. texture object)
592 OGLContext.setScratchSurface(pConfigInfo);
593
594 RenderBuffer buf = rq.getBuffer();
595 rq.ensureCapacityAndAlignment(12, 4);
596 buf.putInt(DISPOSE_SURFACE);
597 buf.putLong(pData);
598
599 // this call is expected to complete synchronously, so flush now
600 rq.flushNow();
601 } finally {
602 rq.unlock();
603 }
604 }
605
606 static void swapBuffers(long window) {
607 OGLRenderQueue rq = OGLRenderQueue.getInstance();
608 rq.lock();
609 try {
610 RenderBuffer buf = rq.getBuffer();
611 rq.ensureCapacityAndAlignment(12, 4);
612 buf.putInt(SWAP_BUFFERS);
613 buf.putLong(window);
614 rq.flushNow();
615 } finally {
616 rq.unlock();
617 }
618 }
619
620 /**
621 * Returns true if OpenGL textures can have non-power-of-two dimensions
622 * when using the basic GL_TEXTURE_2D target.
623 */
624 boolean isTexNonPow2Available() {
625 return graphicsConfig.isCapPresent(CAPS_TEXNONPOW2);
626 }
627
628 /**
629 * Returns true if OpenGL textures can have non-power-of-two dimensions
630 * when using the GL_TEXTURE_RECTANGLE_ARB target (only available when the
631 * GL_ARB_texture_rectangle extension is present).
632 */
633 boolean isTexRectAvailable() {
634 return graphicsConfig.isCapPresent(CAPS_EXT_TEXRECT);
635 }
636
637 public Rectangle getNativeBounds() {
638 OGLRenderQueue rq = OGLRenderQueue.getInstance();
639 rq.lock();
640 try {
641 return new Rectangle(nativeWidth, nativeHeight);
642 } finally {
643 rq.unlock();
644 }
645 }
646
647 /**
648 * Returns true if the surface is an on-screen window surface or
649 * a FBO texture attached to an on-screen CALayer.
650 *
651 * Needed by Mac OS X port.
652 */
653 boolean isOnScreen() {
654 return getType() == WINDOW;
655 }
656 }