luci-mod-status: channel_analysis: use svg grad

Instead of using a second, semitransparent quadliteral of the
same station color to highlight the main 20 MHz channel of a
station with a bandwidht wider than 20 MHz, use a semitransparent,
black svg gradient with the same shape and size.
This has the benefit that it is harder to mistake for a second,
overlain station.

The gradient is black because this way it can be reused for
all stations, instead of having to create a separate one for
each station color.

Signed-off-by: Frank Löffler <frank.loeffler@uni-jena.de>

modules/luci-mod-status/htdocs/luci-static/resources/svg/channel_analysis.svg

@@ -16,4 +16,21 @@
 
 	<line x1="0" y1="90%" x2="100%" y2="90%" style="stroke:black;stroke-width:0.1" />
 	<text id="label_10" x="10" y="89%" style="fill:#eee; font-size:9pt; font-family:sans-serif; text-shadow:1px 1px 1px #000">-90 dbm</text>
+	<defs>
+		<linearGradient id="GradientVerticalCenteredBlack">
+			<stop class="stopinvis" offset="0%" />
+			<stop class="stopblack" offset="50%" />
+			<stop class="stopinvis" offset="100%" />
+		</linearGradient>
+	</defs>
+	<style>
+		.stopinvis {
+			stop-color: "transparent";
+			stop-opacity: 0;
+		}
+		.stopblack {
+			stop-color: "black";
+			stop-opacity: .1;
+		}
+	</style>
 </svg>

modules/luci-mod-status/htdocs/luci-static/resources/view/status/channel_analysis.js

@@ -63,7 +63,41 @@ return view.extend({
 		if (scanCache[res.bssid].graph == null)
 			scanCache[res.bssid].graph = [];
 
-		function add_channel_to_graph(chan_analysis, res, scanCache, i, channel, channel_width, label) {
+		channels.forEach(function(channel) {
+			if (scanCache[res.bssid].graph[i] == null) {
+				var group = document.createElementNS('http://www.w3.org/2000/svg', 'g'),
+					line = document.createElementNS('http://www.w3.org/2000/svg', 'polyline'),
+					text = document.createElementNS('http://www.w3.org/2000/svg', 'text'),
+					color = scanCache[res.bssid].color;
+
+				line.setAttribute('style', 'fill:'+color+'4f'+';stroke:'+color+';stroke-width:0.5');
+				text.setAttribute('style', 'fill:'+color+';font-size:9pt; font-family:sans-serif; text-shadow:1px 1px 1px #000');
+				text.appendChild(document.createTextNode(res.ssid || res.bssid));
+
+				group.appendChild(line)
+				group.appendChild(text)
+
+				chan_analysis.graph.firstElementChild.appendChild(group);
+				scanCache[res.bssid].graph[i] = { group : group, line : line, text : text };
+			}
+			if (channel_width > 2) {
+				if (!("main" in scanCache[res.bssid].graph[i])) {
+					var main = document.createElementNS('http://www.w3.org/2000/svg', 'polyline');
+					main.setAttribute('style', 'fill:url(#GradientVerticalCenteredBlack)');
+					scanCache[res.bssid].graph[i].group.appendChild(main)
+					chan_analysis.graph.firstElementChild.lastElementChild.appendChild(main);
+					scanCache[res.bssid].graph[i]["main"] = main;
+				}
+				var main_offset = offset_tbl[res.channel],
+					points = [
+					(main_offset-(step*(2  )))+','+height,
+					(main_offset-(step*(2-1)))+','+height_diff,
+					(main_offset+(step*(2-1)))+','+height_diff,
+					(main_offset+(step*(2  )))+','+height
+				];
+				scanCache[res.bssid].graph[i].main.setAttribute('points', points);
+			}
+
 			var chan_offset = offset_tbl[channel],
 				points = [
 				(chan_offset-(step*(channel_width  )))+','+height,
@@ -72,41 +106,12 @@ return view.extend({
 				(chan_offset+(step*(channel_width  )))+','+height
 			];
 
-			if (scanCache[res.bssid].graph[i] == null) {
+			scanCache[res.bssid].graph[i].text.setAttribute('x', offset_tbl[res.channel]-step);
-				var group = document.createElementNS('http://www.w3.org/2000/svg', 'g'),
+			scanCache[res.bssid].graph[i].text.setAttribute('y', height_diff - 2);
-					line = document.createElementNS('http://www.w3.org/2000/svg', 'polyline'),
-					text = null,
-					color = scanCache[res.bssid].color;
-
-				line.setAttribute('style', 'fill:'+color+'4f'+';stroke:'+color+';stroke-width:0.5');
-				group.appendChild(line)
-
-				if (label != null) {
-					text = document.createElementNS('http://www.w3.org/2000/svg', 'text');
-					text.setAttribute('style', 'fill:'+color+';font-size:9pt; font-family:sans-serif; text-shadow:1px 1px 1px #000');
-					text.appendChild(document.createTextNode(label));
-					group.appendChild(text)
-				}
-
-				chan_analysis.graph.firstElementChild.appendChild(group);
-				scanCache[res.bssid].graph[i] = { group : group, line : line, text : text };
-			}
-
-			if (scanCache[res.bssid].graph[i].text != null) {
-				scanCache[res.bssid].graph[i].text.setAttribute('x', offset_tbl[res.channel]-step);
-				scanCache[res.bssid].graph[i].text.setAttribute('y', height_diff - 2);
-			}
 			scanCache[res.bssid].graph[i].line.setAttribute('points', points);
 			scanCache[res.bssid].graph[i].group.style.zIndex = res.signal*-1;
 			scanCache[res.bssid].graph[i].group.style.opacity = res.stale ? '0.5' : null;
-		}
-
-		channels.forEach(function(channel) {
-			add_channel_to_graph(chan_analysis, res, scanCache, i, channel, channel_width, res.ssid || res.bssid);
 		})
-		if (channel_width > 2) {
-			add_channel_to_graph(chan_analysis, res, scanCache, i+1, res.channel, 2, null);
-		}
 	},
 
 	create_channel_graph: function(chan_analysis, freq_tbl, band) {