QgsMapUnitScale fixes:

- add docs - add missing SIP bindings - remove unnecessary cast from double->float->double - add unit tests (cherry-picked from f0a2fc1)
qgis · Nov 18, 2015 · a1479a7 · a1479a7
1 parent 7b59fc0
commit a1479a7
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Showing 4 changed files with 136 additions and 4 deletions.
diff --git a/python/core/qgsmapunitscale.sip b/python/core/qgsmapunitscale.sip
@@ -13,13 +13,25 @@ class QgsMapUnitScale
 #include <qgsmapunitscale.h>
 %End
   public:
-    QgsMapUnitScale();
-    QgsMapUnitScale( float _minScale, float _maxScale );
+
+    /** Constructor for QgsMapUnitScale
+     * @param minScale minimum allowed scale, or 0.0 if no minimum scale set
+     * @param maxScale maximum allowed scale, or 0.0 if no maximum scale set
+     */
+    QgsMapUnitScale( double minScale = 0.0, double maxScale = 0.0 );
 
     /** The minimum scale, or 0.0 if unset */
     double minScale;
     /** The maximum scale, or 0.0 if unset */
     double maxScale;
 
+    /** Computes a map units per pixel scaling factor, respecting the minimum and maximum scales
+     * set for the object.
+     * @param c render context
+     * @returns map units per pixel, limited between minimum and maximum scales
+     */
     double computeMapUnitsPerPixel( const QgsRenderContext& c ) const;
+
+    bool operator==( const QgsMapUnitScale& other ) const;
+    bool operator!=( const QgsMapUnitScale& other ) const;
 };
diff --git a/src/core/qgsmapunitscale.h b/src/core/qgsmapunitscale.h
@@ -21,17 +21,35 @@
 #include <QtCore>
 #include "qgsrendercontext.h"
 
+/**
+ * \class QgsMapUnitScale
+ * \brief Struct for storing maximum and minimum scales for measurements in map units
+ *
+ * For measurements in map units, a minimum and a maximum scale can be defined.
+ * Outside this range, the measurements aren't scaled anymore proportionally to
+ * the map scale.
+ */
+
 class CORE_EXPORT QgsMapUnitScale
 {
   public:
-    QgsMapUnitScale() : minScale( 0.0 ), maxScale( 0.0 ) {}
-    QgsMapUnitScale( float _minScale, float _maxScale ) : minScale( _minScale ), maxScale( _maxScale ) {}
+
+    /** Constructor for QgsMapUnitScale
+     * @param minScale minimum allowed scale, or 0.0 if no minimum scale set
+     * @param maxScale maximum allowed scale, or 0.0 if no maximum scale set
+     */
+    QgsMapUnitScale( double minScale = 0.0, double maxScale = 0.0 ) : minScale( minScale ), maxScale( maxScale ) {}
 
     /** The minimum scale, or 0.0 if unset */
     double minScale;
     /** The maximum scale, or 0.0 if unset */
     double maxScale;
 
+    /** Computes a map units per pixel scaling factor, respecting the minimum and maximum scales
+     * set for the object.
+     * @param c render context
+     * @returns map units per pixel, limited between minimum and maximum scales
+     */
     double computeMapUnitsPerPixel( const QgsRenderContext& c ) const
     {
       double mup = c.mapToPixel().mapUnitsPerPixel();

diff --git a/tests/src/python/CMakeLists.txt b/tests/src/python/CMakeLists.txt
@@ -16,6 +16,7 @@ ADD_PYTHON_TEST(PyQgsLogger test_qgslogger.py)
 ADD_PYTHON_TEST(PyQgsCoordinateTransform test_qgscoordinatetransform.py)
 ADD_PYTHON_TEST(PyQgsRectangle test_qgsrectangle.py)
 ADD_PYTHON_TEST(PyQgsRelation test_qgsrelation.py)
+ADD_PYTHON_TEST(PyQgsMapUnitScale test_qgsmapunitscale.py)
 ADD_PYTHON_TEST(PyQgsSpatialIndex test_qgsspatialindex.py)
 ADD_PYTHON_TEST(PyQgsComposerHtml test_qgscomposerhtml.py)
 ADD_PYTHON_TEST(PyQgsComposition test_qgscomposition.py)

diff --git a/tests/src/python/test_qgsmapunitscale.py b/tests/src/python/test_qgsmapunitscale.py
@@ -0,0 +1,101 @@
+# -*- coding: utf-8 -*-
+"""QGIS Unit tests for QgsMapUnitScale.
+
+.. note:: This program 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.
+"""
+__author__ = 'Nyall Dawson'
+__date__ = '2015-09'
+__copyright__ = 'Copyright 2015, The QGIS Project'
+# This will get replaced with a git SHA1 when you do a git archive
+__revision__ = '$Format:%H$'
+
+import qgis
+
+from qgis.core import (QgsMapUnitScale, QgsRenderContext, QgsMapSettings, QgsRectangle)
+from PyQt4.QtCore import QSize
+from utilities import (TestCase, unittest)
+
+
+class PyQgsMapUnitScale(TestCase):
+
+    def testConstructor(self):
+        #test creating QgsMapUnitScale
+        c = QgsMapUnitScale()
+        self.assertEqual(c.minScale, 0)
+        self.assertEqual(c.maxScale, 0)
+
+        c = QgsMapUnitScale(0.0001, 0.005)
+        self.assertEqual(c.minScale, 0.0001)
+        self.assertEqual(c.maxScale, 0.005)
+
+    def testEquality(self):
+        #test equality operator
+
+        c1 = QgsMapUnitScale(0.0001, 0.005)
+        c2 = QgsMapUnitScale(0.0001, 0.005)
+        self.assertEqual(c1, c2)
+
+        c2.minScale = 0.0004
+        self.assertNotEqual(c1, c2)
+
+        c2.minScale = 0.0001
+        c2.maxScale = 0.007
+        self.assertNotEqual(c1, c2)
+
+        c2.maxScale = 0.005
+        self.assertEqual(c1, c2)
+
+    def testMapUnitsPerPixel(self):
+        #test computeMapUnitsPerPixel
+
+        ms = QgsMapSettings()
+        ms.setExtent(QgsRectangle(0, 0, 100, 100))
+        ms.setOutputSize(QSize(100, 50))
+        r = QgsRenderContext.fromMapSettings(ms)
+
+        #renderer scale should be about 1:291937841
+
+        #start with no min/max scale
+        c = QgsMapUnitScale()
+
+        mup = c.computeMapUnitsPerPixel(r)
+        self.assertAlmostEqual(mup, 2.0, places=5)
+
+        #add a minimum scale less than the renderer scale, so should be no change
+        c.minScale = 1 / 350000000.0
+        mup = c.computeMapUnitsPerPixel(r)
+        self.assertAlmostEqual(mup, 2.0, places=5)
+
+        #minimum scale greater than the renderer scale, so should be limited to minScale
+        c.minScale = 1 / 150000000.0
+        mup = c.computeMapUnitsPerPixel(r)
+        self.assertAlmostEqual(mup, 1.0276160, places=5)
+        c.minScale = 1 / 50000000.0
+        mup = c.computeMapUnitsPerPixel(r)
+        self.assertAlmostEqual(mup, 0.3425386, places=5)
+        c.minScale = 1 / 350000000.0
+
+        #add a maximum scale greater than the renderer scale, so should be no change
+        c.maxScale = 1 / 150000000.0
+        mup = c.computeMapUnitsPerPixel(r)
+        self.assertAlmostEqual(mup, 2.0, places=5)
+
+        #maximum scale less than the renderer scale, so should be limited to maxScale
+        c.maxScale = 1 / 350000000.0
+        mup = c.computeMapUnitsPerPixel(r)
+        self.assertAlmostEqual(mup, 2.3977706, places=5)
+        c.maxScale = 1 / 500000000.0
+        mup = c.computeMapUnitsPerPixel(r)
+        self.assertAlmostEqual(mup, 3.4253867, places=5)
+
+        #test resetting to min/max
+        c.minScale = 0
+        c.maxScale = 0
+        mup = c.computeMapUnitsPerPixel(r)
+        self.assertAlmostEqual(mup, 2.0, places=5)
+
+if __name__ == '__main__':
+    unittest.main()