From a64ca2b4bf3c173e54d9adb5cf8e045750596a82 Mon Sep 17 00:00:00 2001
From: Frederic Junod <frederic.junod@camptocamp.com>
Date: Mon, 12 Nov 2018 21:23:46 +0100
Subject: [PATCH] Use CSS z-index to order layers

---
 rendering/cases/vector-zindex/expected.png | Bin 0 -> 1461 bytes
 rendering/cases/vector-zindex/main.js      |  50 +++++++++++++++++++++
 src/ol/renderer/Composite.js               |  14 +++---
 3 files changed, 59 insertions(+), 5 deletions(-)
 create mode 100644 rendering/cases/vector-zindex/expected.png
 create mode 100644 rendering/cases/vector-zindex/main.js

diff --git a/rendering/cases/vector-zindex/expected.png b/rendering/cases/vector-zindex/expected.png
new file mode 100644
index 0000000000000000000000000000000000000000..4dad10a9583b04df4529b119f6576dd3e3ce235f
GIT binary patch
literal 1461
zcmeAS@N?(olHy`uVBq!ia0y~yU<5K5893O0R7}x|GzJFN8c!F;kcv5PZ`iK)$(A|x
zusThCZd2B45tD5#a|1L)TFx(cChTz}TB#{R#cAc&pdVa9fh#U_Oixn2_(G#pY2$Ux
zGQa0@ntM~9?OT^(I{B;0|1(jq&Cky|X~5&$;B|Q;JHs($h5#Ri1v3~N3>h1em>7<-
zFm!P;hzK)is10I?8}Z5f2i|{u;#u@L?bEB!O`A4-yLsu-t->!EoAU4P`24Zjw=GfP
zm|Ro*`^(Fp9BO@XYwMHK)7Q`6ykWu|o0&2D=H%S?Q2jhvhAH5|)6-8*Onh>7cD{A}
z_jgau%}u$!F5X)F@n?C5#@*%n|337eB(8t$n!*1!4A1U7K7R7w-;=LieP27<Z*uzi
zH%!mw${v`ryY}~Q`F|<7XM3gX>*fCGFd00bXaE1>*7foK_gMZgu4J82JljlF-u~Z>
zTSt#R`TKjmHGjPr<Ba0TCx2brZT)O^I30s}(vy38Q_jyz`TQ)!Xy)qV6TkX4KL7t}
zW98>tUw4(~zp+k#1_`(%llXlq&(EueuTwc1fB4KSpGn2fCv}TYZf)JTe5U7J#)=;X
zmK6nWG$Z<7n(VB%w=Btc<CzxpUHiaP?PUK0RcqI&g|F|kJ$mNVJ;t1ylWKk#d=pu7
z{ZZ1Ve}8WTpIP!wmSM_kz5|~=-4Om@yra*4jWxq^zg}C$*QRsT($9nS@f}#`eDdSt
zWdDOzbL{8KSO5($Uj5tuK>eCED%aPm^UJBczt?Na`#=5lwI?4QJ~`5vl9~A?Gi?^b
znVlz7YG2=#{k-<KD8s42pOT5mcnRlp_4+nXyQ#oXoL5;nXX_a@VDe!)P(PFButAS4
z%l>n>x1T&W_vG{Q_qXRgKKA72=ak#q;*G`Y*{mBZx7St|y}a~&{qCBZhwmTYTX5i2
z)~53OPj7B+pSyq09Glu%K7Vb_*iPSZpk$U!)s#7wlXZ0d{I2BYKKb(U$;Zd#{)v?_
zq|USP%)9Fq7Iv*qB{IsZ?2SjCtoOIK(&ct_`oJ>7tZE1rAVdWFKQ^{CM+MG#J<bOf
O#|)mXelF{r5}E+wydS>+

literal 0
HcmV?d00001

diff --git a/rendering/cases/vector-zindex/main.js b/rendering/cases/vector-zindex/main.js
new file mode 100644
index 0000000000..937284279c
--- /dev/null
+++ b/rendering/cases/vector-zindex/main.js
@@ -0,0 +1,50 @@
+import Map from '../../../src/ol/Map.js';
+import View from '../../../src/ol/View.js';
+import Feature from '../../../src/ol/Feature.js';
+import LineString from '../../../src/ol/geom/LineString.js';
+import VectorLayer from '../../../src/ol/layer/Vector.js';
+import VectorSource from '../../../src/ol/source/Vector.js';
+import Style from '../../../src/ol/style/Style.js';
+import Stroke from '../../../src/ol/style/Stroke.js';
+
+
+const vectorSourceRed = new VectorSource();
+const vectorSourceBlue = new VectorSource();
+let feature;
+
+feature = new Feature({
+  geometry: new LineString([[-60, 20], [45, 20]])
+});
+feature.setStyle(new Style({
+  stroke: new Stroke({color: '#f00', width: 10})
+}));
+vectorSourceRed.addFeature(feature);
+
+
+feature = new Feature({
+  geometry: new LineString([[0, -50], [0, 60]])
+});
+feature.setStyle(new Style({
+  stroke: new Stroke({color: '#00f', width: 16})
+}));
+vectorSourceBlue.addFeature(feature);
+
+new Map({
+  pixelRatio: 1,
+  layers: [
+    new VectorLayer({
+      zIndex: 1,
+      source: vectorSourceRed
+    }),
+    new VectorLayer({
+      source: vectorSourceBlue
+    })
+  ],
+  target: 'map',
+  view: new View({
+    center: [0, 0],
+    resolution: 1
+  })
+});
+
+render();
diff --git a/src/ol/renderer/Composite.js b/src/ol/renderer/Composite.js
index 8e6f00c2da..01312e7a40 100644
--- a/src/ol/renderer/Composite.js
+++ b/src/ol/renderer/Composite.js
@@ -1,12 +1,11 @@
 /**
  * @module ol/renderer/canvas/Map
  */
-import {stableSort} from '../array.js';
 import {CLASS_UNSELECTABLE} from '../css.js';
 import {visibleAtResolution} from '../layer/Layer.js';
 import RenderEvent from '../render/Event.js';
 import RenderEventType from '../render/EventType.js';
-import MapRenderer, {sortByZIndex} from './Map.js';
+import MapRenderer from './Map.js';
 import SourceState from '../source/State.js';
 import {replaceChildren} from '../dom.js';
 
@@ -79,8 +78,6 @@ class CompositeMapRenderer extends MapRenderer {
     this.dispatchRenderEvent(RenderEventType.PRECOMPOSE, frameState);
 
     const layerStatesArray = frameState.layerStatesArray;
-    stableSort(layerStatesArray, sortByZIndex);
-
     const viewResolution = frameState.viewState.resolution;
 
     this.children_.length = 0;
@@ -91,7 +88,14 @@ class CompositeMapRenderer extends MapRenderer {
       }
 
       const layer = layerState.layer;
-      this.children_.push(layer.render(frameState));
+      const element = layer.render(frameState);
+      if (element) {
+        const zIndex = layerState.zIndex;
+        if (zIndex !== element.style.zIndex) {
+          element.style.zIndex = zIndex;
+        }
+        this.children_.push(element);
+      }
     }
 
     replaceChildren(this.element_, this.children_);