silx.gui.plot.PlotWidget: Added support of dashed line gap color

src/silx/gui/plot/backends/BackendBase.py

@@ -88,7 +88,7 @@ def _setPlot(self, plot):
     # Add methods
 
     def addCurve(self, x, y,
-                 color, symbol, linewidth, linestyle,
+                 color, gapcolor, symbol, linewidth, linestyle,
                  yaxis,
                  xerror, yerror,
                  fill, alpha, symbolsize, baseline):
@@ -99,6 +99,8 @@ def addCurve(self, x, y,
         :param color: color(s) to be used
         :type color: string ("#RRGGBB") or (npoints, 4) unsigned byte array or
                      one of the predefined color names defined in colors.py
+        :param Union[str, None] gapcolor:
+            color used to fill dashed line gaps.
         :param str symbol: Symbol to be drawn at each (x, y) position::
 
             - ' ' or '' no symbol

src/silx/gui/plot/backends/BackendMatplotlib.py

@@ -597,7 +597,7 @@ def _getMarkerFromSymbol(self, symbol):
         return symbol
 
     def addCurve(self, x, y,
-                 color, symbol, linewidth, linestyle,
+                 color, gapcolor, symbol, linewidth, linestyle,
                  yaxis,
                  xerror, yerror,
                  fill, alpha, symbolsize, baseline):
@@ -685,6 +685,10 @@ def addCurve(self, x, y,
                                   picker=True,
                                   pickradius=pickradius,
                                   markersize=symbolsize)
+
+            if gapcolor is not None and self._matplotlibVersion >= Version('3.6.0'):
+                for line2d in curveList:
+                    line2d.set_gapcolor(gapcolor)
             artists += list(curveList)
 
             if fill:

src/silx/gui/plot/backends/BackendOpenGL.py

@@ -519,7 +519,7 @@ def _renderItems(self, overlay=False):
                             points[:, 0], points[:, 1],
                             style=item['linestyle'],
                             color=item['color'],
-                            dash2ndColor=item['linebgcolor'],
+                            gapColor=item['linebgcolor'],
                             width=item['linewidth'])
                         context.matrix = self.matScreenProj
                         lines.render(context)
@@ -768,7 +768,7 @@ def _castArrayTo(v):
             raise ValueError('Unsupported data type')
 
     def addCurve(self, x, y,
-                 color, symbol, linewidth, linestyle,
+                 color, gapcolor, symbol, linewidth, linestyle,
                  yaxis,
                  xerror, yerror,
                  fill, alpha, symbolsize, baseline):
@@ -872,6 +872,7 @@ def addCurve(self, x, y,
             yError=yerror,
             lineStyle=linestyle,
             lineColor=color,
+            lineGapColor=gapcolor,
             lineWidth=linewidth,
             marker=symbol,
             markerColor=color,

src/silx/gui/plot/backends/glutils/GLPlotCurve.py

@@ -321,18 +321,18 @@ class GLLines2D(object):
         /* Dashes: [0, x], [y, z]
            Dash period: w */
         uniform vec4 dash;
-        uniform vec4 dash2ndColor;
+        uniform vec4 gapColor;
 
         varying float vDist;
         varying vec4 vColor;
 
         void main(void) {
             float dist = mod(vDist, dash.w);
             if ((dist > dash.x && dist < dash.y) || dist > dash.z) {
-                if (dash2ndColor.a == 0.) {
+                if (gapColor.a == 0.) {
                     discard;  // Discard full transparent bg color
                 } else {
-                    gl_FragColor = dash2ndColor;
+                    gl_FragColor = gapColor;
                 }
             } else {
                 gl_FragColor = vColor;
@@ -343,7 +343,7 @@ class GLLines2D(object):
 
     def __init__(self, xVboData=None, yVboData=None,
                  colorVboData=None, distVboData=None,
-                 style=SOLID, color=(0., 0., 0., 1.), dash2ndColor=None,
+                 style=SOLID, color=(0., 0., 0., 1.), gapColor=None,
                  width=1, dashPeriod=10., drawMode=None,
                  offset=(0., 0.)):
         if (xVboData is not None and
@@ -374,7 +374,7 @@ def __init__(self, xVboData=None, yVboData=None,
         self.useColorVboData = colorVboData is not None
 
         self.color = color
-        self.dash2ndColor = dash2ndColor
+        self.gapColor = gapColor
         self.width = width
         self._style = None
         self.style = style
@@ -439,12 +439,12 @@ def render(self, context):
 
             gl.glUniform4f(program.uniforms['dash'], *dash)
 
-            if self.dash2ndColor is None:
+            if self.gapColor is None:
                 # Use fully transparent color which gets discarded in shader
-                dash2ndColor = (0., 0., 0., 0.)
+                gapColor = (0., 0., 0., 0.)
             else:
-                dash2ndColor = self.dash2ndColor
-            gl.glUniform4f(program.uniforms['dash2ndColor'], *dash2ndColor)
+                gapColor = self.gapColor
+            gl.glUniform4f(program.uniforms['gapColor'], *gapColor)
 
             viewWidth = gl.glGetFloatv(gl.GL_VIEWPORT)[2]
             xNDCPerData = (
@@ -1130,6 +1130,7 @@ def __init__(self, xData, yData, colorData=None,
                  xError=None, yError=None,
                  lineStyle=SOLID,
                  lineColor=(0., 0., 0., 1.),
+                 lineGapColor=None,
                  lineWidth=1,
                  lineDashPeriod=20,
                  marker=SQUARE,
@@ -1211,6 +1212,7 @@ def deduce_baseline(baseline):
         self.lines = GLLines2D()
         self.lines.style = lineStyle
         self.lines.color = lineColor
+        self.lines.gapColor = lineGapColor
         self.lines.width = lineWidth
         self.lines.dashPeriod = lineDashPeriod
         self.lines.offset = self.offset
@@ -1237,6 +1239,8 @@ def deduce_baseline(baseline):
 
     lineColor = _proxyProperty(('lines', 'color'))
 
+    lineGapColor = _proxyProperty(('lines', 'gapColor'))
+
     lineWidth = _proxyProperty(('lines', 'width'))
 
     lineDashPeriod = _proxyProperty(('lines', 'dashPeriod'))

src/silx/gui/plot/items/__init__.py

@@ -32,7 +32,7 @@
 __date__ = "22/06/2017"
 
 from .core import (Item, DataItem,  # noqa
-                   LabelsMixIn, DraggableMixIn, ColormapMixIn,  # noqa
+                   LabelsMixIn, DraggableMixIn, ColormapMixIn, LineGapColorMixIn,  # noqa
                    SymbolMixIn, ColorMixIn, YAxisMixIn, FillMixIn,  # noqa
                    AlphaMixIn, LineMixIn, ScatterVisualizationMixIn,  # noqa
                    ComplexMixIn, ItemChangedType, PointsBase)  # noqa

src/silx/gui/plot/items/core.py

@@ -91,6 +91,9 @@ class ItemChangedType(enum.Enum):
     LINE_BG_COLOR = 'lineBgColorChanged'
     """Item's line background color changed flag."""
 
+    LINE_GAP_COLOR = 'lineGapColorChanged'
+    """Item's dashed line gap color changed flag."""
+
     YAXIS = 'yAxisChanged'
     """Item's Y axis binding changed flag."""
 
@@ -935,6 +938,39 @@ def setColor(self, color, copy=True):
         self._updated(ItemChangedType.COLOR)
 
 
+class LineGapColorMixIn(ItemMixInBase):
+    """Mix-in class for dashed line gap color"""
+
+    _DEFAULT_LINE_GAP_COLOR = None
+    """Default dashed line gap color of the item"""
+
+    def __init__(self):
+        self.__lineGapColor = self._DEFAULT_LINE_GAP_COLOR
+
+    def getLineGapColor(self):
+        """Returns the RGBA color of dashed line gap of the item
+
+        :rtype: 4-tuple of float in [0, 1] or None
+        """
+        return self.__lineGapColor
+
+    def setLineGapColor(self, color):
+        """Set dashed line gap color
+
+        It supports:
+        - color names: e.g., 'green'
+        - color codes: '#RRGGBB' and '#RRGGBBAA'
+        - indexed color names: e.g., 'C0'
+        - RGB(A) sequence of uint8 in [0, 255] or float in [0, 1]
+        - QColor
+
+        :param color: line background color to be used
+        :type color: Union[str, List[int], List[float], QColor, None]
+        """
+        self.__lineGapColor = colors.rgba(color)
+        self._updated(ItemChangedType.LINE_GAP_COLOR)
+
+
 class YAxisMixIn(ItemMixInBase):
     """Mix-in class for item with yaxis"""
 

src/silx/gui/plot/items/curve.py

@@ -36,7 +36,7 @@
 from ....utils.deprecation import deprecated_warning
 from ... import colors
 from .core import (PointsBase, LabelsMixIn, ColorMixIn, YAxisMixIn,
-                   FillMixIn, LineMixIn, SymbolMixIn,
+                   FillMixIn, LineMixIn, LineGapColorMixIn, SymbolMixIn,
                    BaselineMixIn, HighlightedMixIn, _Style)
 
 
@@ -53,10 +53,11 @@ class CurveStyle(_Style):
     :param Union[float,None] linewidth: Width of the line
     :param Union[str,None] symbol: Symbol for markers
     :param Union[float,None] symbolsize: Size of the markers
+    :param gapcolor: Color of gaps of dashed line
     """
 
     def __init__(self, color=None, linestyle=None, linewidth=None,
-                 symbol=None, symbolsize=None):
+                 symbol=None, symbolsize=None, gapcolor=None):
         if color is None:
             self._color = None
         else:
@@ -80,6 +81,8 @@ def __init__(self, color=None, linestyle=None, linewidth=None,
 
         self._symbolsize = None if symbolsize is None else float(symbolsize)
 
+        self._gapcolor = None if gapcolor is None else colors.rgba(gapcolor)
+
     def getColor(self, copy=True):
         """Returns the color or None if not set.
 
@@ -93,6 +96,13 @@ def getColor(self, copy=True):
         else:
             return self._color
 
+    def getLineGapColor(self):
+        """Returns the color of dashed line gaps or None if not set.
+
+        :rtype: Union[List[float],None]
+        """
+        return self._gapcolor
+
     def getLineStyle(self):
         """Return the type of the line or None if not set.
 
@@ -145,13 +155,14 @@ def __eq__(self, other):
                     self.getLineStyle() == other.getLineStyle() and
                     self.getLineWidth() == other.getLineWidth() and
                     self.getSymbol() == other.getSymbol() and
-                    self.getSymbolSize() == other.getSymbolSize())
+                    self.getSymbolSize() == other.getSymbolSize() and
+                    self.getLineGapColor() == other.getLineGapColor())
         else:
             return False
 
 
 class Curve(PointsBase, ColorMixIn, YAxisMixIn, FillMixIn, LabelsMixIn,
-            LineMixIn, BaselineMixIn, HighlightedMixIn):
+            LineMixIn, LineGapColorMixIn, BaselineMixIn, HighlightedMixIn):
     """Description of a curve"""
 
     _DEFAULT_Z_LAYER = 1
@@ -178,6 +189,7 @@ def __init__(self):
         FillMixIn.__init__(self)
         LabelsMixIn.__init__(self)
         LineMixIn.__init__(self)
+        LineGapColorMixIn.__init__(self)
         BaselineMixIn.__init__(self)
         HighlightedMixIn.__init__(self)
 
@@ -196,6 +208,7 @@ def _addBackendRenderer(self, backend):
 
         return backend.addCurve(xFiltered, yFiltered,
                                 color=style.getColor(),
+                                gapcolor=style.getLineGapColor(),
                                 symbol=style.getSymbol(),
                                 linestyle=style.getLineStyle(),
                                 linewidth=style.getLineWidth(),
@@ -255,20 +268,24 @@ def getCurrentStyle(self):
             linewidth = style.getLineWidth()
             symbol = style.getSymbol()
             symbolsize = style.getSymbolSize()
+            gapcolor = style.getLineGapColor()
 
             return CurveStyle(
                 color=self.getColor() if color is None else color,
                 linestyle=self.getLineStyle() if linestyle is None else linestyle,
                 linewidth=self.getLineWidth() if linewidth is None else linewidth,
                 symbol=self.getSymbol() if symbol is None else symbol,
-                symbolsize=self.getSymbolSize() if symbolsize is None else symbolsize)
+                symbolsize=self.getSymbolSize() if symbolsize is None else symbolsize,
+                gapcolor=self.getLineGapColor() if gapcolor is None else gapcolor,
+            )
 
         else:
             return CurveStyle(color=self.getColor(),
                               linestyle=self.getLineStyle(),
                               linewidth=self.getLineWidth(),
                               symbol=self.getSymbol(),
-                              symbolsize=self.getSymbolSize())
+                              symbolsize=self.getSymbolSize(),
+                              gapcolor=self.getLineGapColor())
 
     def setData(self, x, y, xerror=None, yerror=None, baseline=None, copy=True):
         """Set the data of the curve.

src/silx/gui/plot/items/histogram.py

@@ -36,7 +36,7 @@
 
 from ....utils.proxy import docstring
 from .core import (DataItem, AlphaMixIn, BaselineMixIn, ColorMixIn, FillMixIn,
-                   LineMixIn, YAxisMixIn, ItemChangedType)
+                   LineMixIn, LineGapColorMixIn, YAxisMixIn, ItemChangedType)
 from ._pick import PickingResult
 
 _logger = logging.getLogger(__name__)
@@ -99,7 +99,7 @@ def _getHistogramCurve(histogram, edges):
 
 # TODO: Yerror, test log scale
 class Histogram(DataItem, AlphaMixIn, ColorMixIn, FillMixIn,
-                LineMixIn, YAxisMixIn, BaselineMixIn):
+                LineMixIn, LineGapColorMixIn, YAxisMixIn, BaselineMixIn):
     """Description of an histogram"""
 
     _DEFAULT_Z_LAYER = 1
@@ -123,6 +123,7 @@ def __init__(self):
         ColorMixIn.__init__(self)
         FillMixIn.__init__(self)
         LineMixIn.__init__(self)
+        LineGapColorMixIn.__init__(self)
         YAxisMixIn.__init__(self)
 
         self._histogram = ()
@@ -162,6 +163,7 @@ def _addBackendRenderer(self, backend):
 
         return backend.addCurve(x, y,
                                 color=self.getColor(),
+                                gapcolor=self.getLineGapColor(),
                                 symbol='',
                                 linestyle=self.getLineStyle(),
                                 linewidth=self.getLineWidth(),

src/silx/gui/plot/items/scatter.py

@@ -532,6 +532,7 @@ def _addBackendRenderer(self, backend):
             rgbacolors = self.__applyColormapToData()
             return backend.addCurve(xFiltered, yFiltered,
                                     color=rgbacolors[mask],
+                                    gapcolor=None,
                                     symbol=self.getSymbol(),
                                     linewidth=0,
                                     linestyle="",
@@ -632,6 +633,7 @@ def _addBackendRenderer(self, backend):
                     # single point, render as a square points
                     return backend.addCurve(xFiltered, yFiltered,
                                             color=rgbacolors[mask],
+                                            gapcolor=None,
                                             symbol='s',
                                             linewidth=0,
                                             linestyle="",

src/silx/gui/plot/test/testPlotWidget.py

@@ -576,6 +576,15 @@ def testPlotCurveComplexData(self):
         data = numpy.arange(100.) + 1j
         self.plot.addCurve(x=data, y=data, xerror=data, yerror=data)
 
+    def testPlotCurveGapColor(self):
+        """Test dashed curve with gap color"""
+        data = numpy.arange(100)
+        self.plot.addCurve(x=data, y=data, legend='curve1', linestyle='--', color='blue')
+        curve = self.plot.getCurve('curve1')
+        assert curve.getLineGapColor() is None
+        curve.setLineGapColor('red')
+        assert curve.getLineGapColor() == (1., 0., 0., 1.)
+
 
 class TestPlotHistogram(PlotWidgetTestCase):
     """Basic tests for add Histogram"""
@@ -598,6 +607,21 @@ def testPlotBaseline(self):
                                z=2,
                                fill=True)
 
+    def testPlotGapColor(self):
+        """Test dashed histogram with gap color"""
+        data = numpy.arange(100)
+        self.plot.addHistogram(
+            histogram=self.histogram,
+            edges=self.edges,
+            legend='histogram1',
+            color='blue',
+        )
+        histogram = self.plot.getItems()[0]
+        assert histogram.getLineGapColor() is None
+        histogram.setLineGapColor('red')
+        assert histogram.getLineGapColor() == (1., 0., 0., 1.)
+        histogram.setLineStyle(':')
+
 
 class TestPlotScatter(PlotWidgetTestCase, ParametricTestCase):
     """Basic tests for addScatter"""