---
title: CssLayout
order: 12
layout: page
---
[[layout.csslayout]]
= [classname]#CssLayout#
[classname]#CssLayout# allows strong control over styling of the components
contained inside the layout. The components are contained in a simple DOM
structure consisting of [literal]#++
++# elements. By default, the contained
components are laid out horizontally and wrap naturally when they reach the
width of the layout, but you can control this and most other behaviour with CSS.
You can also inject custom CSS for each contained component. As
[classname]#CssLayout# has a very simple DOM structure and no dynamic rendering
logic, relying purely on the built-in rendering logic of the browsers, it is the
fastest of the layout components.
The basic use of [classname]#CssLayout# is just like with any other layout
component:
[source, java]
----
CssLayout layout = new CssLayout();
// Component with a layout-managed caption and icon
TextField tf = new TextField("A TextField");
tf.setIcon(new ThemeResource("icons/user.png"));
layout.addComponent(tf);
// Labels are 100% wide by default so must unset width
Label label = new Label("A Label");
label.setWidth(Sizeable.SIZE_UNDEFINED, 0);
layout.addComponent(label);
layout.addComponent(new Button("A Button"));
----
The result is shown in <
>. Notice that the
default spacing and alignment of the layout is quite crude and CSS styling is
nearly always needed.
[[figure.layout.csslayout.basic]]
.Basic Use of [classname]#CssLayout#
image::img/csslayout-basic.png[]
The [literal]#++display++# attribute of [classname]#CssLayout# is
[literal]#++inline-block++# by default, so the components are laid out
horizontally following another. [classname]#CssLayout# has 100% width by
default. If the components reach the width of the layout, they are wrapped to
the next "line" just as text would be. If you add a component with 100% width,
it will take an entire line by wrapping before and after the component.
[[layout.csslayout.injection]]
== CSS Injection
Overriding the [methodname]#getCss()# method allows injecting custom CSS for
each component. The CSS returned by the method is inserted in the
[parameter]#style# attribute of the [literal]#++++# element of the
component, so it will override any style definitions made in CSS files.
[source, java]
----
CssLayout layout = new CssLayout() {
@Override
protected String getCss(Component c) {
if (c instanceof Label) {
// Color the boxes with random colors
int rgb = (int) (Math.random()*(1<<24));
return "background: #" + Integer.toHexString(rgb);
}
return null;
}
};
layout.setWidth("400px"); // Causes to wrap the contents
// Add boxes of various sizes
for (int i=0; i<40; i++) {
Label box = new Label(" ", ContentMode.HTML);
box.addStyleName("flowbox");
box.setWidth((float) Math.random()*50,
Sizeable.UNITS_PIXELS);
box.setHeight((float) Math.random()*50,
Sizeable.UNITS_PIXELS);
layout.addComponent(box);
}
----
The style name added to the components allows making common styling in a CSS
file:
[source, css]
----
.v-label-flowbox {
border: thin black solid;
}
----
<
> shows the rendered result.
[[figure.layout.csslayout.getcss]]
.Use of [methodname]#getCss()# and line wrap
image::img/csslayout-getcss.png[]
[[layout.csslayout.compatibility]]
== Browser Compatibility
The stregth of the [classname]#CssLayout# is also its weakness. Much of the
logic behind the other layout components is there to give nice default behaviour
and to handle the differences in different browsers. Some browsers, no need to
say which, are notoriously incompatible with the CSS standards, so they require
a lot of custom CSS. You may need to make use of the browser-specific style
classes in the root element of the
application.////
TODO: described in <xref
linkend="advanced.browserinfo"/>
////
Some features in the other layouts are not even solvable in pure CSS, at least
in all browsers.
[[layout.csslayout.css]]
== Styling with CSS
[source, css]
----
.v-csslayout {}
.v-csslayout-margin {}
.v-csslayout-container {}
----
The [classname]#CssLayout# component has [literal]#++v-csslayout++# root style.
The margin element with [literal]#++v-csslayout-margin++# style is always
enabled. The components are contained in an element with
[literal]#++v-csslayout-container++# style.
For example, we could style the basic [classname]#CssLayout# example shown
earlier as follows:
[source, css]
----
/* Have the caption right of the text box, bottom-aligned */
.csslayoutexample .mylayout .v-csslayout-container {
direction: rtl;
line-height: 24px;
vertical-align: bottom;
}
/* Have some space before and after the caption */
.csslayoutexample .mylayout .v-csslayout-container .v-caption {
padding-left: 3px;
padding-right: 10px;
}
----
The example would now be rendered as shown in
<>.
[[figure.layout.csslayout.styling]]
.Styling [classname]#CssLayout#
image::img/csslayout-styling.png[]
Captions and icons that are managed by the layout are contained in an element
with [literal]#++v-caption++# style. These caption elements are contained flat
at the same level as the actual component elements. This may cause problems with
wrapping in [literal]#++inline-block++# mode, as wrapping can occur between the
caption and its corresponding component element just as well as between
components. Such use case is therefore not feasible.
'>45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
|