[gnome-maps/wip/mlundblad/dont-use-offscreen-window: 2/7] Add a utility function to draw the colored badges for transit lines

[Marcus Lundblad <mlundblad src gnome org>]

commit a53c458fdfbde59fbaaa0ecbc6c0f8add7ffb5a4
Author: Marcus Lundblad <ml update uu se>
Date:   Sat Mar 16 13:45:34 2019 +0100

    Add a utility function to draw the colored badges for transit lines
    
    Adds a new gfx module with this function to enable reusing the
    drawing routine when re-implementing the print layouts using Cairo.

 src/gfx.js                           | 61 ++++++++++++++++++++++++++++++++++++
 src/org.gnome.Maps.src.gresource.xml |  1 +
 2 files changed, 62 insertions(+)
---
diff --git a/src/gfx.js b/src/gfx.js
new file mode 100644
index 0000000..8f6ce6a
--- /dev/null
+++ b/src/gfx.js
@@ -0,0 +1,61 @@
+/* -*- Mode: JS2; indent-tabs-mode: nil; js2-basic-offset: 4 -*- */
+/* vim: set et ts=4 sw=4: */
+/*
+ * Copyright (c) 2019, Marcus Lundblad.
+ *
+ * GNOME Maps is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * GNOME Maps is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with GNOME Maps; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Marcus Lundblad <ml update uu se>
+ */
+
+const Color = imports.color;
+
+/**
+ * Draws a colored badged with rounded corners and an optional outline.
+ *
+ * cr: A Cairo context to draw into
+ * bgColor: The fill color to draw the background with, represented as
+ *          a string with 8-bit HEX-encoded RGB values
+ * outlineColor: The color to use for the outline, or null if no outline
+ * x: pixel offset for x-coord of top-left corner of bounding box
+ * y: pixel offset for y-coord of top-left corner of bounding box
+ * width: The width to draw the badge
+ * height: The height to draw the badge
+ */
+function drawColoredBagde(cr, bgColor, outlineColor, x, y, width, height) {
+    let bgRed = Color.parseColor(bgColor, 0);
+    let bgGreen = Color.parseColor(bgColor, 1);
+    let bgBlue = Color.parseColor(bgColor, 2);
+    let radius = outlineColor ? 5 : 3;
+
+    cr.newSubPath();
+    cr.arc(width - radius + x, radius + y, radius, -Math.PI / 2, 0);
+    cr.arc(width - radius + x, height - radius + y, radius, 0 , Math.PI / 2);
+    cr.arc(radius + x, height - radius + y, radius, Math.PI / 2, Math.PI);
+    cr.arc(radius + x, radius + y, radius, Math.PI, 3 * Math.PI / 2);
+    cr.closePath();
+
+    cr.setSourceRGB(bgRed, bgGreen, bgBlue);
+    cr.fillPreserve();
+
+    if (outlineColor) {
+        let outlineRed = Color.parseColor(outlineColor, 0);
+        let outlineGreen = Color.parseColor(outlineColor, 1);
+        let outlineBlue = Color.parseColor(outlineColor, 2);
+
+        cr.setSourceRGB(outlineRed, outlineGreen, outlineBlue);
+        cr.setLineWidth(1);
+        cr.stroke();
+    }
+}
diff --git a/src/org.gnome.Maps.src.gresource.xml b/src/org.gnome.Maps.src.gresource.xml
index 2341735..16d777f 100644
--- a/src/org.gnome.Maps.src.gresource.xml
+++ b/src/org.gnome.Maps.src.gresource.xml
@@ -19,6 +19,7 @@
     <file>geoJSONShapeLayer.js</file>
     <file>geoJSONSource.js</file>
     <file>geoJSONStyle.js</file>
+    <file>gfx.js</file>
     <file>gpxShapeLayer.js</file>
     <file>graphHopper.js</file>
     <file>hvt.js</file>