Add some more options to control how a preview pixmap for a color ram…

…p is generated
qgis · Dec 7, 2020 · 928b00a · 928b00a
1 parent e11f64e
commit 928b00a
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Showing 9 changed files with 116 additions and 17 deletions.
diff --git a/python/core/auto_generated/symbology/qgssymbollayerutils.sip.in b/python/core/auto_generated/symbology/qgssymbollayerutils.sip.in
@@ -286,13 +286,19 @@ Returns an icon preview for a color ramp.
 .. seealso:: :py:func:`colorRampPreviewPixmap`
 %End
 
-    static QPixmap colorRampPreviewPixmap( QgsColorRamp *ramp, QSize size, int padding = 0 );
+    static QPixmap colorRampPreviewPixmap( QgsColorRamp *ramp, QSize size, int padding = 0, Qt::Orientation direction = Qt::Horizontal,
+                                           bool flipDirection = false, bool drawTransparentBackground = true );
 %Docstring
 Returns a pixmap preview for a color ramp.
 
 :param ramp: color ramp
 :param size: target pixmap size
 :param padding: space between icon edge and color ramp
+:param direction: direction to render pixmap (since QGIS 3.18)
+:param flipDirection: set to ``True`` to flip the direction of the ramp. For horizontal ``directions``, ramps will be
+                      rendered left to right by default. For vertical ``directions``, ramps will be rendered top to bottom by default. Setting
+                      this flag to ``True`` will reverse these default directions.
+:param drawTransparentBackground: set to ``False`` to disable the checkerboard effect drawn below transparent colors in the ramp
 
 .. seealso:: :py:func:`colorRampPreviewIcon`
 %End

diff --git a/src/core/symbology/qgssymbollayerutils.cpp b/src/core/symbology/qgssymbollayerutils.cpp
@@ -874,7 +874,7 @@ QIcon QgsSymbolLayerUtils::colorRampPreviewIcon( QgsColorRamp *ramp, QSize size,
   return QIcon( colorRampPreviewPixmap( ramp, size, padding ) );
 }
 
-QPixmap QgsSymbolLayerUtils::colorRampPreviewPixmap( QgsColorRamp *ramp, QSize size, int padding )
+QPixmap QgsSymbolLayerUtils::colorRampPreviewPixmap( QgsColorRamp *ramp, QSize size, int padding, Qt::Orientation direction, bool flipDirection, bool drawTransparentBackground )
 {
   QPixmap pixmap( size );
   pixmap.fill( Qt::transparent );
@@ -883,16 +883,38 @@ QPixmap QgsSymbolLayerUtils::colorRampPreviewPixmap( QgsColorRamp *ramp, QSize s
   painter.begin( &pixmap );
 
   //draw stippled background, for transparent images
-  drawStippledBackground( &painter, QRect( padding, padding, size.width() - padding * 2, size.height() - padding  * 2 ) );
+  if ( drawTransparentBackground )
+    drawStippledBackground( &painter, QRect( padding, padding, size.width() - padding * 2, size.height() - padding  * 2 ) );
 
   // antialiasing makes the colors duller, and no point in antialiasing a color ramp
   // painter.setRenderHint( QPainter::Antialiasing );
-  for ( int i = 0; i < size.width(); i++ )
+  switch ( direction )
   {
-    QPen pen( ramp->color( static_cast< double >( i ) / size.width() ) );
-    painter.setPen( pen );
-    painter.drawLine( i, 0 + padding, i, size.height() - 1 - padding );
+    case Qt::Horizontal:
+    {
+      for ( int i = 0; i < size.width(); i++ )
+      {
+        QPen pen( ramp->color( static_cast< double >( i ) / size.width() ) );
+        painter.setPen( pen );
+        const int x = flipDirection ? size.width() - i - 1 : i;
+        painter.drawLine( x, 0 + padding, x, size.height() - 1 - padding );
+      }
+      break;
+    }
+
+    case Qt::Vertical:
+    {
+      for ( int i = 0; i < size.height(); i++ )
+      {
+        QPen pen( ramp->color( static_cast< double >( i ) / size.height() ) );
+        painter.setPen( pen );
+        const int y = flipDirection ? size.height() - i - 1 : i;
+        painter.drawLine( 0 + padding, y, size.width() - 1 - padding, y );
+      }
+      break;
+    }
   }
+
   painter.end();
   return pixmap;
 }

diff --git a/src/core/symbology/qgssymbollayerutils.h b/src/core/symbology/qgssymbollayerutils.h
@@ -273,9 +273,15 @@ class CORE_EXPORT QgsSymbolLayerUtils
      * \param ramp color ramp
      * \param size target pixmap size
      * \param padding space between icon edge and color ramp
+     * \param direction direction to render pixmap (since QGIS 3.18)
+     * \param flipDirection set to TRUE to flip the direction of the ramp. For horizontal \a directions, ramps will be
+     * rendered left to right by default. For vertical \a directions, ramps will be rendered top to bottom by default. Setting
+     * this flag to TRUE will reverse these default directions.
+     * \param drawTransparentBackground set to FALSE to disable the checkerboard effect drawn below transparent colors in the ramp
      * \see colorRampPreviewIcon()
      */
-    static QPixmap colorRampPreviewPixmap( QgsColorRamp *ramp, QSize size, int padding = 0 );
+    static QPixmap colorRampPreviewPixmap( QgsColorRamp *ramp, QSize size, int padding = 0, Qt::Orientation direction = Qt::Horizontal,
+                                           bool flipDirection = false, bool drawTransparentBackground = true );
 
     static void drawStippledBackground( QPainter *painter, QRect rect );
 

diff --git a/tests/src/python/test_qgssymbollayerutils.py b/tests/src/python/test_qgssymbollayerutils.py
@@ -11,20 +11,26 @@
 __copyright__ = 'Copyright 2016, The QGIS Project'
 
 import qgis  # NOQA
-
-from qgis.core import (QgsSymbolLayerUtils,
-                       QgsMarkerSymbol,
-                       QgsArrowSymbolLayer,
-                       QgsUnitTypes)
+from qgis.PyQt.QtCore import (
+    QSizeF,
+    QPointF,
+    QMimeData,
+    QDir,
+    QSize,
+    Qt
+)
 from qgis.PyQt.QtGui import (
     QColor,
     QPolygonF,
     QImage
 )
-from qgis.PyQt.QtCore import (
-    QSizeF,
-    QPointF,
-    QMimeData
+from qgis.core import (
+    QgsSymbolLayerUtils,
+    QgsMarkerSymbol,
+    QgsArrowSymbolLayer,
+    QgsUnitTypes,
+    QgsRenderChecker,
+    QgsGradientColorRamp
 )
 from qgis.testing import unittest, start_app
 
@@ -33,6 +39,16 @@
 
 class PyQgsSymbolLayerUtils(unittest.TestCase):
 
+    @classmethod
+    def setUpClass(cls):
+        cls.report = "<h1>Python QgsPointCloudRgbRenderer Tests</h1>\n"
+
+    @classmethod
+    def tearDownClass(cls):
+        report_file_path = "%s/qgistest.html" % QDir.tempPath()
+        with open(report_file_path, 'a') as report_file:
+            report_file.write(cls.report)
+
     def testEncodeDecodeSize(self):
         s = QSizeF()
         string = QgsSymbolLayerUtils.encodeSize(s)
@@ -408,6 +424,55 @@ def testColorFromMimeData(self):
         color, has_alpha = QgsSymbolLayerUtils.colorFromMimeData(data)
         self.assertFalse(color.isValid())
 
+    def testPreviewColorRampHorizontal(self):
+        r = QgsGradientColorRamp(QColor(200, 0, 0, 200), QColor(0, 200, 0, 255))
+
+        pix = QgsSymbolLayerUtils.colorRampPreviewPixmap(r, QSize(200, 100))
+        img = QImage(pix)
+        self.assertTrue(self.imageCheck('color_ramp_horizontal', 'color_ramp_horizontal', img))
+
+    def testPreviewColorRampHorizontalNoCheckboard(self):
+        r = QgsGradientColorRamp(QColor(200, 0, 0, 200), QColor(0, 200, 0, 255))
+
+        pix = QgsSymbolLayerUtils.colorRampPreviewPixmap(r, QSize(200, 100), drawTransparentBackground=False)
+        img = QImage(pix)
+        self.assertTrue(self.imageCheck('color_ramp_no_check', 'color_ramp_no_check', img))
+
+    def testPreviewColorRampHorizontalFlipped(self):
+        r = QgsGradientColorRamp(QColor(200, 0, 0, 200), QColor(0, 200, 0, 255))
+
+        pix = QgsSymbolLayerUtils.colorRampPreviewPixmap(r, QSize(200, 100), flipDirection=True)
+        img = QImage(pix)
+        self.assertTrue(self.imageCheck('color_ramp_horizontal_flipped', 'color_ramp_horizontal_flipped', img))
+
+    def testPreviewColorRampVertical(self):
+        r = QgsGradientColorRamp(QColor(200, 0, 0, 200), QColor(0, 200, 0, 255))
+
+        pix = QgsSymbolLayerUtils.colorRampPreviewPixmap(r, QSize(100, 200), direction=Qt.Vertical)
+        img = QImage(pix)
+        self.assertTrue(self.imageCheck('color_ramp_vertical', 'color_ramp_vertical', img))
+
+    def testPreviewColorRampVerticalFlipped(self):
+        r = QgsGradientColorRamp(QColor(200, 0, 0, 200), QColor(0, 200, 0, 255))
+
+        pix = QgsSymbolLayerUtils.colorRampPreviewPixmap(r, QSize(100, 200), direction=Qt.Vertical, flipDirection=True)
+        img = QImage(pix)
+        self.assertTrue(self.imageCheck('color_ramp_vertical_flipped', 'color_ramp_vertical_flipped', img))
+
+    def imageCheck(self, name, reference_image, image):
+        self.report += "<h2>Render {}</h2>\n".format(name)
+        temp_dir = QDir.tempPath() + '/'
+        file_name = temp_dir + name + ".png"
+        image.save(file_name, "PNG")
+        checker = QgsRenderChecker()
+        checker.setControlPathPrefix("symbol_layer_utils")
+        checker.setControlName("expected_" + reference_image)
+        checker.setRenderedImage(file_name)
+        checker.setColorTolerance(2)
+        result = checker.compareImages(name, 20)
+        PyQgsSymbolLayerUtils.report += checker.report()
+        return result
+
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/...l_layer_utils/expected_color_ramp_horizontal/expected_color_ramp_horizontal.png b/...l_layer_utils/expected_color_ramp_horizontal/expected_color_ramp_horizontal.png
diff --git a/...pected_color_ramp_horizontal_flipped/expected_color_ramp_horizontal_flipped.png b/...pected_color_ramp_horizontal_flipped/expected_color_ramp_horizontal_flipped.png
diff --git a/...ymbol_layer_utils/expected_color_ramp_no_check/expected_color_ramp_no_check.png b/...ymbol_layer_utils/expected_color_ramp_no_check/expected_color_ramp_no_check.png
diff --git a/...ymbol_layer_utils/expected_color_ramp_vertical/expected_color_ramp_vertical.png b/...ymbol_layer_utils/expected_color_ramp_vertical/expected_color_ramp_vertical.png
diff --git a/...s/expected_color_ramp_vertical_flipped/expected_color_ramp_vertical_flipped.png b/...s/expected_color_ramp_vertical_flipped/expected_color_ramp_vertical_flipped.png