-
Notifications
You must be signed in to change notification settings - Fork 420
Expand file tree
/
Copy pathch20s07.html
More file actions
693 lines (555 loc) · 32.9 KB
/
Copy pathch20s07.html
File metadata and controls
693 lines (555 loc) · 32.9 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
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
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>20.7. SVG 图形库</title><link rel="stylesheet" type="text/css" href="docbook.css" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><meta name="keywords" content="php,pear,pecl,phar, python, , " /><link rel="home" href="index.html" title="Netkiller Python 手札" /><link rel="up" href="graphics.html" title="第 20 章 图形开发" /><link rel="prev" href="pillow/index.html" title="20.6. PIL（Python Imaging Library）Python 图像处理库" /><link rel="next" href="netkiller-chart.html" title="20.8. Netkiller SVG 图形库" /></head><body><a xmlns="" href="//www.netkiller.cn/">Home</a> | <a xmlns="" href="//netkiller.github.io/">简体中文</a> | <a xmlns="" href="http://netkiller.sourceforge.net/">繁体中文</a> | <a xmlns="" href="/journal/index.html">杂文</a>
| <a xmlns="" href="https://github.com/netkiller">Github</a> | <a xmlns="" href="https://zhuanlan.zhihu.com/netkiller">知乎专栏</a> | <a xmlns="" href="https://www.facebook.com/bg7nyt">Facebook</a> | <a xmlns="" href="http://cn.linkedin.com/in/netkiller/">Linkedin</a> | <a xmlns="" href="https://www.youtube.com/user/bg7nyt/videos">Youtube</a> | <a xmlns="" href="//www.netkiller.cn/home/donations.html">打赏(Donations)</a> | <a xmlns="" href="//www.netkiller.cn/home/about.html">About</a><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">20.7. SVG 图形库</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="pillow/index.html">上一页</a> </td><th width="60%" align="center">第 20 章 图形开发</th><td width="20%" align="right"> <a accesskey="n" href="netkiller-chart.html">下一页</a></td></tr></table><hr /></div><table xmlns=""><tr><td><iframe src="//ghbtns.com/github-btn.html?user=netkiller&repo=netkiller.github.io&type=watch&count=true&size=large" height="30" width="170" frameborder="0" scrolling="0" style="width:170px; height: 30px;" allowTransparency="true"></iframe></td><td><iframe src="//ghbtns.com/github-btn.html?user=netkiller&repo=netkiller.github.io&type=fork&count=true&size=large" height="30" width="170" frameborder="0" scrolling="0" style="width:170px; height: 30px;" allowTransparency="true"></iframe></td><td><iframe src="//ghbtns.com/github-btn.html?user=netkiller&type=follow&count=true&size=large" height="30" width="240" frameborder="0" scrolling="0" style="width:240px; height: 30px;" allowTransparency="true"></iframe></td><td></td><td><a href="https://zhuanlan.zhihu.com/netkiller"><img src="/images/logo/zhihu-card-default.svg" height="25" /></a></td><td valign="middle"><a href="https://zhuanlan.zhihu.com/netkiller">知乎专栏</a></td><td></td><td></td><td></td><td></td></tr></table><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="id4855"></a>20.7. SVG 图形库</h2></div></div></div>
<div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="svg.tag"></a>20.7.1. SVG 标签</h3></div></div></div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id1257"></a>20.7.1.1. 符号定义</h4></div></div></div>
<p>symbol元素用来定义一个图形模板对象，它可以用一个use元素实例化。symbol元素对图形的作用是在同一文档中多次使用，添加结构和语义。结构丰富的文档可以更生动地呈现出来，类似讲演稿或盲文，从而提升了无障碍。注意，一个symbol元素本身是不呈现的。只有symbol元素的实例（亦即，一个引用了symbol的 use元素）才能呈现。</p>
<pre class="programlisting">
<svg>
<!-- symbol definition NEVER draw -->
<symbol id="sym01" viewBox="0 0 150 110">
<circle cx="50" cy="50" r="40" stroke-width="8" stroke="red" fill="red" />
<circle
cx="90"
cy="60"
r="40"
stroke-width="8"
stroke="green"
fill="white" />
</symbol>
<!-- actual drawing by "use" element -->
<use xlink:href="#sym01" x="0" y="0" width="100" height="50" />
<use xlink:href="#sym01" x="0" y="50" width="75" height="38" />
<use xlink:href="#sym01" x="0" y="100" width="50" height="25" />
</svg>
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id1258"></a>20.7.1.2. 矩形</h4></div></div></div>
<p>绘制圆角矩形</p>
<pre class="programlisting">
<svg width="300px" height="300px" viewBox="0 0 200 200">
<!-- rx 和 ry 相等, 逐渐增大 -->
<rect x="10" y="10" width="20" height="40" rx="2" ry="2"
style="stroke: black; fill: none;"/>
<rect x="40" y="10" width="20" height="40" rx="5"
style="stroke: black; fill: none;"/>
<rect x="70" y="10" width="20" height="40" ry="10"
style="stroke: black; fill: none;"/>
<!-- rx 和 ry 不相等 -->
<rect x="10" y="60" width="20" height="40" rx="10" ry="5"
style="stroke: black; fill: none;"/>
<rect x="40" y="60" width="20" height="40" rx="5" ry="10"
style="stroke: black; fill: none;"/>
</svg>
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id1259"></a>20.7.1.3. 圆形</h4></div></div></div>
<pre class="programlisting">
<circle
cx="x-coordinate" <!-- 圆心的 x 坐标 -->
cy="y-coordinate" <!-- 圆心的 y 坐标 -->
r="radius" <!-- 圆的半径 -->
fill="fill-color" <!-- 圆的填充颜色 -->
stroke="stroke-color" <!-- 圆的描边颜色 -->
stroke-width="width" <!-- 圆的描边宽度 -->
/>
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="svg.path"></a>20.7.1.4. 路径</h4></div></div></div>
<div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="id1261"></a>贝塞尔曲线</h5></div></div></div>
<div class="section"><div class="titlepage"><div><div><h6 class="title"><a id="id1260"></a>两次贝塞尔曲线</h6></div></div></div>
<p>拥有两个控制点的贝塞尔曲线</p>
<pre class="screen">
<path d="M{x},{y} C{cx1},{cy1} {cx2},{cy2} {x1},{y1}" id="路径" stroke="blue" stroke-width="2"></path>
起点：M{x},{y}
起点控制点：C{cx1},{cy1}
终点控制点：{cx2},{cy2}
终点：{x1},{y1}
</pre>
<p>下面代码生成类似 mindmap 思维导图的连接线</p>
<pre class="programlisting">
<path d="M0,200 C200,200 200,0 400,0" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C200,200 200,50 400,50" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C200,200 200,100 400,100" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C200,200 200,150 400,150" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C200,200 200,200 400,200" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C200,200 200,250 400,250" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C200,200 200,300 400,300" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C200,200 200,350 400,350" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C200,200 200,400 400,400" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C200,200 200,450 400,450" id="路径" stroke="#FFA500" stroke-width="2"></path>
</pre>
<p>进一步增加复杂度，生成二级子集，同时在起点处增加两个圆圈点缀。</p>
<pre class="programlisting">
<path d="M0,200 C150,200 200,0 300,0" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C150,200 200,50 300,50" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C150,200 200,100 300,100" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C150,200 200,150 300,150" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C150,200 200,200 300,200" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C150,200 200,250 300,250" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C150,200 200,300 300,300" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C150,200 200,350 300,350" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C150,200 200,400 300,400" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M0,200 C150,200 200,450 300,450" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M300,200 C400,200 500,100 600,100" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M300,200 C400,200 500,150 600,150" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M300,200 C400,200 500,200 600,200" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M300,200 C400,200 500,250 600,250" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M300,200 C400,200 500,250 600,250" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M300,200 C400,200 500,300 600,300" id="路径" stroke="#FFA500" stroke-width="2"></path>
<path d="M300,200 C400,200 500,350 600,350" id="路径" stroke="#FFA500" stroke-width="2"></path>
<circle cx="0" cy="200" r="5" fill="white" stroke="blue" stroke-width="2"/>
<circle cx="300" cy="200" r="5" fill="white" stroke="green" stroke-width="2"/>
</pre>
<p>两端延伸出一段横线，横线上增加文字</p>
<pre class="programlisting">
<text text-anchor="middle" x="50" y="120" fill="purple" stroke="none">咖啡豆分类</text>
<text text-anchor="middle" x="350" y="45" fill="red" stroke="none">阿拉比卡咖啡豆</text>
<path d="M0,125 L100,125 C200,125 200,50 300,50 L 400,50" id="路径" stroke="red" stroke-width="2"></path>
<text text-anchor="middle" x="350" y="95" fill="green" stroke="none">罗布斯塔咖啡豆</text>
<path d="M0,125 L100,125 C200,125 200,100 300,100 L 400,100" id="路径" stroke="green" stroke-width="2"></path>
<text text-anchor="middle" x="350" y="145" fill="orange" stroke="none">利比里亚咖啡豆</text>
<path d="M0,125 L100,125 C200,125 200,150 300,150 L 400,150" id="路径" stroke="orange" stroke-width="2"></path>
<text text-anchor="middle" x="350" y="195" fill="blue" stroke="none">埃克萨斯咖啡豆</text>
<path d="M0,125 L100,125 C200,125 200,200 300,200 L 400,200" id="路径" stroke="blue" stroke-width="2"></path>
<circle cx="100" cy="125" r="5" fill="white" stroke="blue" stroke-width="2"/>
</pre>
</div>
</div>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id1265"></a>20.7.1.5. script</h4></div></div></div>
<div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="id1262"></a>绘制三角形</h5></div></div></div>
<pre class="programlisting">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 400 300" width="400" height="300">
<!-- 样式定义 -->
<style>
.triangle { fill: #4a90e2; fill-opacity: 0.7; stroke: #333; stroke-width: 2; }
.angle-label { font-family: Arial; font-size: 14px; font-weight: bold; }
.angle-arc { stroke: #666; stroke-width: 1.5; fill: none; }
.side-label { font-family: Arial; font-size: 12px; }
.info { font-family: Arial; font-size: 12px; fill: #333; }
</style>
<!-- 背景和说明文字 -->
<rect width="100%" height="100%" fill="#f9f9f9" />
<text x="200" y="20" text-anchor="middle" class="info">指定内角的三角形 (30°, 60°, 90°)</text>
<!-- 计算参数：三个内角之和必须为180° -->
<defs>
<data id="angles" value="30,60,90" /> <!-- 可修改此处的角度值 -->
<data id="sideLength" value="150" /> <!-- 基准边长 -->
</defs>
<!-- 三角形绘制：通过JavaScript计算坐标 -->
<script type="text/javascript"><![CDATA[
// 获取参数
const anglesStr = document.getElementById('angles').getAttribute('value');
const [A, B, C] = anglesStr.split(',').map(Number);
const a = parseFloat(document.getElementById('sideLength').getAttribute('value'));
// 验证角度和为180°
if (A + B + C !== 180) {
alert(`角度和必须为180°，当前总和为${A+B+C}°`);
}
// 转换角度为弧度
const radA = A * Math.PI / 180;
const radB = B * Math.PI / 180;
const radC = C * Math.PI / 180;
// 利用正弦定理计算其他两边长度: a/sinA = b/sinB = c/sinC
const b = a * Math.sin(radB) / Math.sin(radA);
const c = a * Math.sin(radC) / Math.sin(radA);
// 计算三角形三个顶点坐标（以(100, 200)为第一个顶点）
const x1 = 100, y1 = 200;
const x2 = x1 + c, y2 = y1;
const x3 = x1 + b * Math.cos(radA), y3 = y1 - b * Math.sin(radA);
// 创建三角形路径
const triangle = document.createElementNS("http://www.w3.org/2000/svg", "path");
triangle.setAttribute('d', `M ${x1},${y1} L ${x2},${y2} L ${x3},${y3} Z`);
triangle.setAttribute('class', 'triangle');
document.querySelector('svg').appendChild(triangle);
// 绘制角度标记
function drawAngleMarker(x, y, angleRad, radius, label, isInside) {
const startAngle = isInside ? Math.PI : 0;
const endAngle = isInside ? Math.PI - angleRad : angleRad;
// 计算弧线
const arc = document.createElementNS("http://www.w3.org/2000/svg", "path");
const startX = x + radius * Math.cos(startAngle);
const startY = y - radius * Math.sin(startAngle);
const endX = x + radius * Math.cos(endAngle);
const endY = y - radius * Math.sin(endAngle);
const largeArcFlag = angleRad > Math.PI ? 1 : 0;
arc.setAttribute('d', `M ${startX},${startY} A ${radius},${radius} 0 ${largeArcFlag},1 ${endX},${endY}`);
arc.setAttribute('class', 'angle-arc');
document.querySelector('svg').appendChild(arc);
// 添加角度标签
const labelAngle = isInside ? startAngle - angleRad / 2 : angleRad / 2;
const labelX = x + (radius + 15) * Math.cos(labelAngle);
const labelY = y - (radius + 15) * Math.sin(labelAngle);
const text = document.createElementNS("http://www.w3.org/2000/svg", "text");
text.setAttribute('x', labelX);
text.setAttribute('y', labelY);
text.setAttribute('text-anchor', 'middle');
text.setAttribute('class', 'angle-label');
text.textContent = `${label}°`;
document.querySelector('svg').appendChild(text);
}
// 绘制三个角的标记
drawAngleMarker(x1, y1, radA, 30, A, true);
drawAngleMarker(x2, y2, radB, 30, B, true);
drawAngleMarker(x3, y3, radC, 30, C, true);
// 添加边长标签
function addSideLabel(x1, y1, x2, y2, label) {
const text = document.createElementNS("http://www.w3.org/2000/svg", "text");
const midX = (x1 + x2) / 2;
const midY = (y1 + y2) / 2;
text.setAttribute('x', midX);
text.setAttribute('y', midY - 5);
text.setAttribute('text-anchor', 'middle');
text.setAttribute('class', 'side-label');
text.textContent = label;
document.querySelector('svg').appendChild(text);
}
addSideLabel(x1, y1, x2, y2, `c = ${c.toFixed(1)}`);
addSideLabel(x2, y2, x3, y3, `a = ${a}`);
addSideLabel(x3, y3, x1, y1, `b = ${b.toFixed(1)}`);
] ] ></script>
</svg>
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="id1263"></a>绘制多边形</h5></div></div></div>
<pre class="programlisting">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 400 400" width="400" height="400">
<!-- 样式定义 -->
<style>
.polygon { fill: #4a90e2; fill-opacity: 0.7; stroke: #333; stroke-width: 2; }
.control-panel { font-family: Arial; font-size: 14px; }
.label { fill: #333; }
.value-display { font-weight: bold; }
</style>
<!-- 背景 -->
<rect width="100%" height="100%" fill="#f9f9f9" />
<!-- 控制参数 -->
<defs>
<data id="sides" value="6" /> <!-- 多边形边数 -->
<data id="radius" value="150" /> <!-- 多边形半径（中心点到顶点的距离） -->
<data id="rotation" value="0" /> <!-- 旋转角度（度） -->
<data id="centerX" value="200" /> <!-- 中心点X坐标 -->
<data id="centerY" value="200" /> <!-- 中心点Y坐标 -->
</defs>
<!-- 说明文字 -->
<text x="200" y="30" text-anchor="middle" class="label">正多边形绘制 (边数: <tspan id="sides-display" class="value-display">6</tspan>)</text>
<text x="200" y="370" text-anchor="middle" class="label" font-size="12">可修改边数参数查看不同多边形</text>
<!-- 多边形绘制逻辑 -->
<script type="text/javascript"><![CDATA[
// 获取参数
const sides = parseInt(document.getElementById('sides').getAttribute('value'));
const radius = parseFloat(document.getElementById('radius').getAttribute('value'));
const rotation = parseFloat(document.getElementById('rotation').getAttribute('value'));
const centerX = parseFloat(document.getElementById('centerX').getAttribute('value'));
const centerY = parseFloat(document.getElementById('centerY').getAttribute('value'));
// 验证边数（至少3条边）
if (sides < 3) {
alert("多边形边数必须至少为3");
}
// 更新显示的边数
document.getElementById('sides-display').textContent = sides;
// 计算每个顶点的坐标
const points = [];
const rotationRad = rotation * Math.PI / 180; // 转换旋转角度为弧度
for (let i = 0; i < sides; i++) {
// 计算每个顶点的角度（弧度）
// 从顶部开始（-90度），加上旋转角度，再加上每个顶点的角度偏移
const angle = rotationRad - Math.PI / 2 + (2 * Math.PI * i / sides);
// 计算坐标
const x = centerX + radius * Math.cos(angle);
const y = centerY + radius * Math.sin(angle);
points.push(`${x},${y}`);
}
// 创建多边形元素
const polygon = document.createElementNS("http://www.w3.org/2000/svg", "polygon");
polygon.setAttribute('points', points.join(' '));
polygon.setAttribute('class', 'polygon');
document.querySelector('svg').appendChild(polygon);
// 绘制中心点
const center = document.createElementNS("http://www.w3.org/2000/svg", "circle");
center.setAttribute('cx', centerX);
center.setAttribute('cy', centerY);
center.setAttribute('r', 5);
center.setAttribute('fill', '#ff6b6b');
document.querySelector('svg').appendChild(center);
] ]> </script>
</svg>
</pre>
<pre class="screen">
基本参数设定：
边数（sides）：决定多边形的形状，必须至少为 3
半径（radius）：从中心到顶点的距离
中心点坐标（centerX, centerY）：多边形在 SVG 中的位置
旋转角度（rotation）：控制多边形的朝向
顶点坐标计算：
每个顶点之间的角度间隔 = 2π / 边数（弧度）
第 i 个顶点的角度 = 旋转角度 + 起始角度（-90 度，从顶部开始） + 角度间隔 × i
使用三角函数计算坐标：
x = 中心 x + 半径 × cos (角度)
y = 中心 y + 半径 × sin (角度)
绘制多边形：
将所有顶点坐标按顺序连接，形成闭合的多边形
修改 sides 值：
3：三角形
4：正方形
5：五边形
6：六边形
8：八边形等
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h5 class="title"><a id="id1264"></a>雷达图</h5></div></div></div>
<pre class="programlisting">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 600 500" width="600" height="500">
<!-- 样式定义 -->
<style>
.axis-line { stroke: #ccc; stroke-width: 1; }
.grid-line { stroke: #eee; stroke-width: 1; }
.data-polygon-1 { fill: rgba(54, 162, 235, 0.2); stroke: rgba(54, 162, 235, 1); stroke-width: 2; }
.data-polygon-2 { fill: rgba(75, 192, 192, 0.2); stroke: rgba(75, 192, 192, 1); stroke-width: 2; }
.dimension-label { font-family: Arial; font-size: 14px; fill: #333; }
.legend-item { font-family: Arial; font-size: 12px; fill: #333; }
.title { font-family: Arial; font-size: 18px; font-weight: bold; fill: #333; }
.center-circle { fill: #fff; }
</style>
<!-- 雷达图参数配置 -->
<defs>
<!-- 维度标签 -->
<data id="dimensions" value="性能,易用性,稳定性,安全性,性价比,扩展性"></data>
<!-- 数据值 (0-100)，多组数据用|分隔 -->
<data id="data" value="80,65,90,75,60,85|70,80,65,90,75,60"></data>
<!-- 图例标签 -->
<data id="legends" value="产品A,产品B"></data>
<!-- 配置参数 -->
<data id="centerX" value="300"></data> <!-- 中心点X坐标 -->
<data id="centerY" value="250"></data> <!-- 中心点Y坐标 -->
<data id="maxRadius" value="180"></data> <!-- 最大半径 -->
<data id="levels" value="5"></data> <!-- 网格层数 -->
</defs>
<!-- 标题 -->
<text x="300" y="30" text-anchor="middle" class="title">产品多维度评价雷达图</text>
<!-- 雷达图绘制逻辑 -->
<script type="text/javascript"><![CDATA[
// 获取配置参数
const dimensions = document.getElementById('dimensions').getAttribute('value').split(',');
const dataGroups = document.getElementById('data').getAttribute('value').split('|').map(group =>
group.split(',').map(Number)
);
const legends = document.getElementById('legends').getAttribute('value').split(',');
const centerX = parseFloat(document.getElementById('centerX').getAttribute('value'));
const centerY = parseFloat(document.getElementById('centerY').getAttribute('value'));
const maxRadius = parseFloat(document.getElementById('maxRadius').getAttribute('value'));
const levels = parseInt(document.getElementById('levels').getAttribute('value'));
const numDimensions = dimensions.length;
// 计算每个维度的角度（弧度）
const getAngle = (index) => {
// 从顶部开始（-90度），每个维度平均分配360度
return (index * 2 * Math.PI / numDimensions) - Math.PI / 2;
};
// 计算坐标
const getCoordinates = (index, value) => {
const angle = getAngle(index);
const radius = (value / 100) * maxRadius; // 数据值转换为半径比例
return {
x: centerX + radius * Math.cos(angle),
y: centerY + radius * Math.sin(angle)
};
};
// 绘制网格线和坐标轴
for (let level = 1; level <= levels; level++) {
const radius = (level / levels) * maxRadius;
const points = [];
// 绘制网格多边形
for (let i = 0; i < numDimensions; i++) {
const angle = getAngle(i);
points.push(`${centerX + radius * Math.cos(angle)},${centerY + radius * Math.sin(angle)}`);
}
points.push(points[0]); // 闭合多边形
const grid = document.createElementNS("http://www.w3.org/2000/svg", "polyline");
grid.setAttribute('points', points.join(' '));
grid.setAttribute('class', 'grid-line');
document.querySelector('svg').appendChild(grid);
}
// 绘制轴线
for (let i = 0; i < numDimensions; i++) {
const angle = getAngle(i);
const endX = centerX + maxRadius * Math.cos(angle);
const endY = centerY + maxRadius * Math.sin(angle);
const axis = document.createElementNS("http://www.w3.org/2000/svg", "line");
axis.setAttribute('x1', centerX);
axis.setAttribute('y1', centerY);
axis.setAttribute('x2', endX);
axis.setAttribute('y2', endY);
axis.setAttribute('class', 'axis-line');
document.querySelector('svg').appendChild(axis);
// 绘制维度标签（位置略超出最大半径）
const labelOffset = 20;
const labelX = centerX + (maxRadius + labelOffset) * Math.cos(angle);
const labelY = centerY + (maxRadius + labelOffset) * Math.sin(angle);
const label = document.createElementNS("http://www.w3.org/2000/svg", "text");
label.setAttribute('x', labelX);
label.setAttribute('y', labelY);
label.setAttribute('text-anchor', 'middle');
label.setAttribute('dominant-baseline', 'middle');
label.setAttribute('class', 'dimension-label');
label.textContent = dimensions[i];
document.querySelector('svg').appendChild(label);
}
// 绘制中心点
const centerCircle = document.createElementNS("http://www.w3.org/2000/svg", "circle");
centerCircle.setAttribute('cx', centerX);
centerCircle.setAttribute('cy', centerY);
centerCircle.setAttribute('r', 5);
centerCircle.setAttribute('class', 'center-circle');
document.querySelector('svg').appendChild(centerCircle);
// 绘制数据多边形
dataGroups.forEach((data, groupIndex) => {
const points = [];
for (let i = 0; i < numDimensions; i++) {
const coords = getCoordinates(i, data[i]);
points.push(`${coords.x},${coords.y}`);
}
points.push(points[0]); // 闭合多边形
const polygon = document.createElementNS("http://www.w3.org/2000/svg", "polygon");
polygon.setAttribute('points', points.join(' '));
polygon.setAttribute('class', `data-polygon-${groupIndex + 1}`);
document.querySelector('svg').appendChild(polygon);
});
// 绘制图例
legends.forEach((legend, index) => {
const legendX = 450;
const legendY = 100 + index * 30;
// 图例颜色块
const colorBox = document.createElementNS("http://www.w3.org/2000/svg", "rect");
colorBox.setAttribute('x', legendX);
colorBox.setAttribute('y', legendY - 10);
colorBox.setAttribute('width', 15);
colorBox.setAttribute('height', 15);
colorBox.setAttribute('fill', index === 0 ? 'rgba(54, 162, 235, 0.2)' : 'rgba(75, 192, 192, 0.2)');
colorBox.setAttribute('stroke', index === 0 ? 'rgba(54, 162, 235, 1)' : 'rgba(75, 192, 192, 1)');
colorBox.setAttribute('stroke-width', 2);
document.querySelector('svg').appendChild(colorBox);
// 图例文本
const legendText = document.createElementNS("http://www.w3.org/2000/svg", "text");
legendText.setAttribute('x', legendX + 25);
legendText.setAttribute('y', legendY + 3);
legendText.setAttribute('class', 'legend-item');
legendText.textContent = legend;
document.querySelector('svg').appendChild(legendText);
});
]] ></script>
</svg>
</pre>
</div>
</div>
</div>
<div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="drawsvg"></a>20.7.2. drawsvg</h3></div></div></div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id1266"></a>20.7.2.1. 安装</h4></div></div></div>
<pre class="screen">
pip3 install drawsvg -i https://pypi.tuna.tsinghua.edu.cn/simple
pip3 install cairosvg -i https://pypi.tuna.tsinghua.edu.cn/simple
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id1267"></a>20.7.2.2. 绘制多边形</h4></div></div></div>
<pre class="screen">
lines = draw.Lines(
# 坐标
5, 5,
# 横线
200, 5,
# 竖线
200, 40,
# 斜线
200 - 10, 20,
# 横线2
5 + 10, 20,
# 斜线
5, 40,
# 闭合竖线
5,5,
fill='none', stroke='black')
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id1268"></a>20.7.2.3. SVG 事件</h4></div></div></div>
<pre class="screen">
<!DOCTYPE html>
<html>
<body>
<svg width="500" height="150">
<rect x="10" y="10" width="100" height="40"
style="stroke: black; fill: silver; fill-opacity: .4;"
onmouseover="this.style.stroke = 'blue'; this.style['stroke-width'] = 5;"
onmouseout="this.style.stroke = 'green'; this.style['stroke-width'] = 1;"
onclick="this.style['width'] = 300;" />
</svg>
</body>
</html>
</pre>
<pre class="screen">
<!DOCTYPE html>
<html>
<body>
<input id="aa" type="text" value="200" onclick="svg.style['width']=this.value;" />
<svg width="500" height="150">
<rect id='svg' x="10" y="10" width="100" height="40" style="stroke: black; fill: silver; fill-opacity: .4;"
onmouseover="this.style.stroke = 'blue'; this.style['stroke-width'] = 5;"
onmouseout="this.style.stroke = 'green'; this.style['stroke-width'] = 1;"
onclick="this.style['width'] = 300; aa.value='300'" />
</svg>
</body>
</html>
</pre>
</div>
</div>
<div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="CairoSVG"></a>20.7.3. CairoSVG - SVG 转换为 PNG/PDF/PS</h3></div></div></div>
<pre class="screen">
$ pip3 install cairosvg
</pre>
<pre class="screen">
$ cairosvg image.svg -o image.png
</pre>
<pre class="screen">
$ python3
>>> import cairosvg
>>> cairosvg.svg2pdf(url='image.svg', write_to='image.pdf')
</pre>
<p></p>
<pre class="programlisting">
import os
import cairosvg
input_file = os.getcwd() + "/mindmap.svg"
output_file = os.getcwd() + "/mindmap.png"
cairosvg.svg2png(url=input_file, write_to=output_file)
# 设置背景色
cairosvg.svg2png(url=input_file, write_to=output_file, background_color="white")
</pre>
</div>
</div><script xmlns="" type="text/javascript" id="clustrmaps" src="//cdn.clustrmaps.com/map_v2.js?u=r5HG&d=9mi5r_kkDC8uxG8HuY3p4-2qgeeVypAK9vMD-2P6BYM"></script><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="pillow/index.html">上一页</a> </td><td width="20%" align="center"><a accesskey="u" href="graphics.html">上一级</a></td><td width="40%" align="right"> <a accesskey="n" href="netkiller-chart.html">下一页</a></td></tr><tr><td width="40%" align="left" valign="top">20.6. PIL（Python Imaging Library）Python 图像处理库 </td><td width="20%" align="center"><a accesskey="h" href="index.html">起始页</a></td><td width="40%" align="right" valign="top"> 20.8. Netkiller SVG 图形库</td></tr></table></div><script xmlns="">
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','//www.google-analytics.com/analytics.js','ga');
ga('create', 'UA-11694057-1', 'auto');
ga('send', 'pageview');
</script><script xmlns="" async="async">
var _hmt = _hmt || [];
(function() {
var hm = document.createElement("script");
hm.src = "https://hm.baidu.com/hm.js?93967759a51cda79e49bf4e34d0b0f2c";
var s = document.getElementsByTagName("script")[0];
s.parentNode.insertBefore(hm, s);
})();
</script><script xmlns="" async="async">
(function(){
var bp = document.createElement('script');
var curProtocol = window.location.protocol.split(':')[0];
if (curProtocol === 'https') {
bp.src = 'https://zz.bdstatic.com/linksubmit/push.js';
}
else {
bp.src = 'http://push.zhanzhang.baidu.com/push.js';
}
var s = document.getElementsByTagName("script")[0];
s.parentNode.insertBefore(bp, s);
})();
</script></body></html>