Add flowchart useMaxWidth config parameter (#41)

* Add flowchart useMaxWidth config parameter

The useMaxWidth parameter controls whether the diagram will be scaled to fit the available width. The default for this parameter is true, meaning that the diagram will be scaled. For very wide diagrams, this can result in an unreadably small diagram. Setting useMaxWidth to false allows the diagram to remain at a fixed sized. Scrollbars can be added to the area, if desired, with:

.ext-mermaid > div {
	overflow: scroll;
}

* Add flowchart useMaxWidth config parameter

The useMaxWidth parameter controls whether the diagram will be scaled to
fit the available width. The default for this parameter is true, meaning
that the diagram will be scaled. For very wide diagrams, this can result
in an unreadably small diagram. Setting useMaxWidth to false allows the
diagram to remain at a fixed sized. Scrollbars can be added to the area,
if desired, with:

.ext-mermaid > div {
	overflow: scroll;
}

src/MermaidParserFunction.php

@@ -100,15 +100,26 @@ public function parse( array $params ) {
 		foreach ( $params as $key => $param ) {
 
 			if ( strpos( $param, '=' ) !== false ) {
-				list( $k, $v ) = explode( '=', $param, 2 );
+				list( $k, $value ) = array_map( 'trim', explode( '=', $param, 2 ) );
 
-				if ( $k === 'config.theme' ) {
-					$config['theme'] = $v;
+				$keys = explode( '.', $k );
+				if ( count( $keys ) == 1 || $keys[0] !== 'config' ) {
+					continue;
+				}
+				array_shift( $keys );
+
+				if ( $this->parseParam( $keys, [ 'theme' ], $value, $config ) ) {
+					unset( $params[$key] );
+				}
+
+				elseif ( $this->parseParam( $keys, [ 'flowchart' , 'curve' ], $value,
+					$config ) ) {
 					unset( $params[$key] );
 				}
 
-				if ( $k === 'config.flowchart.curve' ) {
-					$config['flowchart'] = [ 'curve' => $v ];
+				elseif ( $this->parseParam( $keys, [ 'flowchart', 'useMaxWidth' ],
+						filter_var($value, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE),
+ 						$config ) ) {
 					unset( $params[$key] );
 				}
 			}
@@ -136,4 +147,21 @@ public function parse( array $params ) {
 		);
 	}
 
+	private function parseParam( $paramKeys, $configKeys, $value, &$config ) {
+
+		if ( $paramKeys !== $configKeys ) {
+			return false;
+		}
+
+		$a = &$config;
+		foreach ( $configKeys as $key ) {
+			if ( !isset( $a[$key] ) ) {
+				$a[$key] = [];
+			}	
+			$a = &$a[$key];
+		}
+		$a = $value;
+
+		return true;
+	}
 }

tests/phpunit/Unit/MermaidParserFunctionTest.php

@@ -104,6 +104,17 @@ public function textProvider() {
 			[ 'A[Hard edge] -->|Link text| B(Round edge)' ],
 			'data-mermaid="{"content":"A[Hard edge] -->|Link text| B(Round edge)"'
 		];
+
+		yield [
+			[ 'graph LR;', 'config.theme=foo', 'config.flowchart.curve=basis' ],
+			'class="ext-mermaid" data-mermaid="{&quot;content&quot;:&quot;graph LR;&quot;,&quot;config&quot;:{&quot;theme&quot;:&quot;foo&quot;,&quot;flowchart&quot;:{&quot;curve&quot;:&quot;basis&quot;}}}"><div class="mermaid-dots"></div></div>'
+		];
+
+		yield [
+			[ 'graph LR;', 'config.theme=foo', 'config.flowchart.useMaxWidth=false' ],
+			'class="ext-mermaid" data-mermaid="{&quot;content&quot;:&quot;graph LR;&quot;,&quot;config&quot;:{&quot;theme&quot;:&quot;foo&quot;,&quot;flowchart&quot;:{&quot;useMaxWidth&quot;:false}}}"><div class="mermaid-dots"></div></div>'
+		];
+
 	}
 
 }