Provide primitive support for RLegend

Just printout title and labels for beginning

Author: linev

scripts/JSRootPainter.v7.js

@@ -4316,6 +4316,7 @@
    JSROOT.addDrawFunc({ name: "ROOT::Experimental::RLine", icon: "img_graph", prereq: "v7more", func: "JSROOT.v7.drawLine", opt: "", direct: true, csstype: "line" });
    JSROOT.addDrawFunc({ name: "ROOT::Experimental::RBox", icon: "img_graph", prereq: "v7more", func: "JSROOT.v7.drawBox", opt: "", direct: true, csstype: "box" });
    JSROOT.addDrawFunc({ name: "ROOT::Experimental::RMarker", icon: "img_graph", prereq: "v7more", func: "JSROOT.v7.drawMarker", opt: "", direct: true, csstype: "marker" });
+   JSROOT.addDrawFunc({ name: "ROOT::Experimental::RLegend", icon: "img_graph", prereq: "v7more", func: "JSROOT.v7.drawLegend", opt: "", direct: true, csstype: "legend" });
 
    JSROOT.v7.TAxisPainter = TAxisPainter;
    JSROOT.v7.TFramePainter = TFramePainter;

scripts/JSRootPainter.v7more.js

@@ -51,6 +51,7 @@
       this.FinishTextDrawing();
    }
 
+   // =================================================================================
 
    function drawLine() {
 
@@ -76,6 +77,7 @@
            .style("stroke-dasharray", JSROOT.Painter.root_line_styles[line_style]);
    }
 
+   // =================================================================================
 
    function drawBox() {
 
@@ -93,7 +95,7 @@
 
     this.CreateG();
 
-    if (fill_style == 0 ) fill_color = "none";
+    if (fill_style == 0) fill_color = "none";
 
     this.draw_g
         .append("svg:rect")
@@ -109,6 +111,7 @@
         .style("stroke-dasharray", JSROOT.Painter.root_line_styles[line_style]);
    }
 
+   // =================================================================================
 
    function drawMarker() {
        var marker       = this.GetObject(),
@@ -128,12 +131,70 @@
                      .call(att.func);
    }
 
+   // =================================================================================
+
+   function drawLegend() {
+
+      var legend       = this.GetObject(),
+          pp           = this.pad_painter(),
+          p1           = pp.GetCoordinate(legend.fP1),
+          p2           = pp.GetCoordinate(legend.fP2),
+          line_width   = this.v7EvalAttr( "box_border_width", 1),
+          line_style   = this.v7EvalAttr( "box_border_style", 1),
+          line_color   = this.v7EvalColor( "box_border_color", "black"),
+          fill_color   = this.v7EvalColor( "box_fill_color", "white"),
+          fill_style   = this.v7EvalAttr( "box_fill_style", 1),
+          text_size    = this.v7EvalAttr( "title_size", 12),
+          text_angle   = -1 * this.v7EvalAttr( "title_angle", 0),
+          text_align   = this.v7EvalAttr( "title_align", 22),
+          text_color   = this.v7EvalColor( "title_color", "black"),
+          text_font    = this.v7EvalAttr( "title_font", 41);
+
+      this.CreateG();
+
+      if (fill_style == 0) fill_color = "none";
+
+      this.draw_g
+         .append("svg:rect")
+         .attr("x", p1.x)
+         .attr("width", p2.x-p1.x)
+         .attr("y", p2.y)
+         .attr("height", p1.y-p2.y)
+         .style("stroke", line_color)
+         .attr("stroke-width", line_width)
+         .attr("fill", fill_color)
+         .style("stroke-dasharray", JSROOT.Painter.root_line_styles[line_style]);
+
+      var nlines = legend.fEntries.length;
+
+      if (legend.fTitle) nlines++;
+
+      var arg = { align: text_align, x: (p1.x+p2.x)/2, rotate: text_angle, color: text_color, latex: 1 };
+
+      this.StartTextDrawing(text_font, text_size);
+
+      var cnt = 0;
+      if (legend.fTitle) {
+         this.DrawText(JSROOT.extend({ y: p2.y - 0.5*(p2.y-p1.y)/(nlines+1), text: legend.fTitle }, arg));
+         cnt++;
+      }
+
+      for (var i=0; i<legend.fEntries.length; ++i) {
+         var entry = legend.fEntries[i];
+         this.DrawText(JSROOT.extend({ y: p2.y - (cnt+0.5)*(p2.y-p1.y)/(nlines+1), text: entry.fLabel }, arg));
+         cnt++;
+      }
+
+      this.FinishTextDrawing();
+  }
+
    // ================================================================================
 
    JSROOT.v7.drawText   = drawText;
    JSROOT.v7.drawLine   = drawLine;
    JSROOT.v7.drawBox    = drawBox;
    JSROOT.v7.drawMarker = drawMarker;
+   JSROOT.v7.drawLegend = drawLegend;
 
    return JSROOT;