Merge pull request #1534 from 72636c/feature/er_use_max_width

Add `er.useMaxWidth` config option

docs/Setup.md

@@ -714,9 +714,21 @@ T = top, B = bottom, L = left, and R = right.
 | --------- | ------------------- | ------- | -------- | ------------------ |
 | fontSize  | Font Size in pixels | Integer |          | Any Positive Value |
 
-**Notes:**Font size (expressed as an integer representing a number of  pixels)
+**Notes:**Font size (expressed as an integer representing a number of pixels)
 **Default value: 12 **
 
+### useMaxWidth
+
+| Parameter   | Description | Type    | Required | Values      |
+| ----------- | ----------- | ------- | -------- | ----------- |
+| useMaxWidth | See Notes   | Boolean | Required | true, false |
+
+**Notes:**
+When this flag is set to true, the diagram width is locked to 100% and
+scaled based on available space. If set to false, the diagram reserves its
+absolute width.
+**Default value: true**.
+
 ## render
 
 Function that renders an svg with a graph from a chart definition. Usage example below.
@@ -757,6 +769,17 @@ mermaidAPI.initialize({
     startOnLoad:true,
     arrowMarkerAbsolute:false,
 
+    er:{
+      diagramPadding:20,
+      layoutDirection:'TB',
+      minEntityWidth:100,
+      minEntityHeight:75,
+      entityPadding:15,
+      stroke:'gray',
+      fill:'honeydew',
+      fontSize:12,
+      useMaxWidth:true,
+    },
     flowchart:{
       diagramPadding:8,
       htmlLabels:true,