Merge branch 'enh/colourbar_scale' into 'master'

Scale parameter for colourbarbitmap

See merge request fsl/fsleyes/widgets!18

fsleyes_widgets/utils/colourbarbitmap.py

@@ -27,7 +27,8 @@ def colourBarBitmap(cmap,
                     alpha=1.0,
                     fontsize=10,
                     bgColour=None,
-                    textColour='#ffffff'):
+                    textColour='#ffffff',
+                    scale=1.0):
     """Plots a colour bar using :mod:`matplotlib`.
 
 
@@ -83,6 +84,8 @@ def colourBarBitmap(cmap,
 
     :arg textColour:   Label colour - can be any colour specification that
                        is accepted by :mod:`matplotlib`.
+
+    :arg scale:        DPI scaling factor.
     """
 
     # These imports are expensive, so we're
@@ -113,7 +116,10 @@ def colourBarBitmap(cmap,
         if labelside == 'left': labelside = 'top'
         else:                   labelside = 'bottom'
 
-    dpi   = 96.0
+    # Default is 96 dpi to an inch
+    winches   = width  / 96.0
+    hinches   = height / 96.0
+    dpi       = scale  * 96.0
     ncols     = cmapResolution
     data      = genColours(cmap, ncols, invert, alpha, gamma)
 
@@ -122,7 +128,7 @@ def colourBarBitmap(cmap,
         data   = np.concatenate((ndata, data), axis=1)
         ncols *= 2
 
-    fig    = mplfig.Figure(figsize=(width / dpi, height / dpi), dpi=dpi)
+    fig     = mplfig.Figure(figsize=(winches, hinches), dpi=dpi)
     canvas  = mplagg.FigureCanvasAgg(fig)
     ax      = fig.add_subplot(111)
 

tests/test_colourbarbitmap.py

@@ -283,6 +283,40 @@ def test_label_and_ticks():
         assert _compare(bmp, fname)
 
 
+def test_scale():
+    scales       = [0.5, 1.0, 2.0, 3.0]
+    orientations = ['horizontal', 'vertical']
+    labelsides   = ['top', 'bottom']
+
+    testcases = it.product(scales,
+                           orientations,
+                           labelsides)
+
+    ticks      = [0.1, 0.9]
+    ticklabels = [str(t) for t in ticks]
+    label      = 'Label'
+
+    for scale, orient, side in testcases:
+
+        if orient[0] == 'v': width, height = 100, 300
+        else:                width, height = 300, 100
+
+        bmp = cbarbmp.colourBarBitmap('Reds',
+                                      width,
+                                      height,
+                                      ticks=ticks,
+                                      ticklabels=ticklabels,
+                                      label=label,
+                                      orientation=orient,
+                                      labelside=side,
+                                      scale=scale,
+                                      textColour=(0, 0, 0.2, 1))
+
+        fname = '_'.join([str(scale), orient, side])
+        fname = 'scale_{}.png'.format(fname)
+        assert _compare(bmp, fname)
+
+
 def test_badargs():
 
     testcases = [