Add rgbToHex, use it in tests

ivmartel · Mar 2, 2022 · 43dd765 · 43dd765
1 parent f7b649b
commit 43dd765
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Showing 2 changed files with 38 additions and 19 deletions.
diff --git a/src/utils/colour.js b/src/utils/colour.js
@@ -37,6 +37,17 @@ dwv.utils.hexToRgb = function (hexStr) {
   };
 };
 
+/**
+ * Convert RGB to its hex equivalent.
+ *
+ * @param {object} rgb The RGB object as {r,g,b}.
+ * @returns {string} A string representing the hex color as '#ab01ef'.
+ */
+dwv.utils.rgbToHex = function (rgb) {
+  return '#' +
+    ((1 << 24) + (rgb.r << 16) + (rgb.g << 8) + rgb.b).toString(16).slice(1);
+};
+
 /**
  * Get the brightness of a RGB colour: calculates
  * the luma (Y) of the YIQ colour space.

diff --git a/tests/utils/colour.test.js b/tests/utils/colour.test.js
@@ -45,25 +45,33 @@ QUnit.test('Test ybrToRgb.', function (assert) {
  * @function module:tests/utils~hexToRgb
  */
 QUnit.test('Test hexToRgb.', function (assert) {
-  var rgb00 = dwv.utils.hexToRgb('#000000');
-  assert.equal(rgb00.r, 0, 'hexToRgb #000000: r');
-  assert.equal(rgb00.g, 0, 'hexToRgb #000000: g');
-  assert.equal(rgb00.b, 0, 'hexToRgb #000000: b');
-
-  var rgb01 = dwv.utils.hexToRgb('#ffffff');
-  assert.equal(rgb01.r, 255, 'hexToRgb #ffffff: r');
-  assert.equal(rgb01.g, 255, 'hexToRgb #ffffff: g');
-  assert.equal(rgb01.b, 255, 'hexToRgb #ffffff: b');
-
-  var rgb02 = dwv.utils.hexToRgb('#7f7f7f');
-  assert.equal(rgb02.r, 127, 'hexToRgb #7f7f7f: r');
-  assert.equal(rgb02.g, 127, 'hexToRgb #7f7f7f: g');
-  assert.equal(rgb02.b, 127, 'hexToRgb #7f7f7f: b');
-
-  var rgb03 = dwv.utils.hexToRgb('#4e33d6');
-  assert.equal(rgb03.r, 78, 'hexToRgb #4e33d6: r');
-  assert.equal(rgb03.g, 51, 'hexToRgb #4e33d6: g');
-  assert.equal(rgb03.b, 214, 'hexToRgb #4e33d6: b');
+  var hex00 = '#000000';
+  var rgb00 = dwv.utils.hexToRgb(hex00);
+  assert.equal(rgb00.r, 0, 'hexToRgb #00: r');
+  assert.equal(rgb00.g, 0, 'hexToRgb #00: g');
+  assert.equal(rgb00.b, 0, 'hexToRgb #00: b');
+  assert.equal(dwv.utils.rgbToHex(rgb00), hex00, 'rgbToHex #00');
+
+  var hex01 = '#ffffff';
+  var rgb01 = dwv.utils.hexToRgb(hex01);
+  assert.equal(rgb01.r, 255, 'hexToRgb #01: r');
+  assert.equal(rgb01.g, 255, 'hexToRgb #01: g');
+  assert.equal(rgb01.b, 255, 'hexToRgb #01: b');
+  assert.equal(dwv.utils.rgbToHex(rgb01), hex01, 'rgbToHex #01');
+
+  var hex02 = '#7f7f7f';
+  var rgb02 = dwv.utils.hexToRgb(hex02);
+  assert.equal(rgb02.r, 127, 'hexToRgb #02: r');
+  assert.equal(rgb02.g, 127, 'hexToRgb #02: g');
+  assert.equal(rgb02.b, 127, 'hexToRgb #02: b');
+  assert.equal(dwv.utils.rgbToHex(rgb02), hex02, 'rgbToHex #02');
+
+  var hex03 = '#4e33d6';
+  var rgb03 = dwv.utils.hexToRgb(hex03);
+  assert.equal(rgb03.r, 78, 'hexToRgb #03: r');
+  assert.equal(rgb03.g, 51, 'hexToRgb #03: g');
+  assert.equal(rgb03.b, 214, 'hexToRgb #03: b');
+  assert.equal(dwv.utils.rgbToHex(rgb03), hex03, 'rgbToHex #03');
 });
 
 /**