Fix WMS DPI scale rounding error

Backported from master PR #42292
qgis · Mar 19, 2021 · 520331c745228ee484de610977a8bbf2c1acd027 · 520331c
1 parent 202f1bf
commit 520331c745228ee484de610977a8bbf2c1acd027
diff --git a/src/server/services/wms/qgswmsrendercontext.cpp b/src/server/services/wms/qgswmsrendercontext.cpp
@@ -172,7 +172,7 @@ qreal QgsWmsRenderContext::dotsPerMm() const
   // Apply DPI parameter if present. This is an extension of QGIS Server
   // compared to WMS 1.3.
   // Because of backwards compatibility, this parameter is optional
-  int dpm = 1 / OGC_PX_M;
+  qreal dpm = 1 / OGC_PX_M;
 
   if ( !mParameters.dpi().isEmpty() )
   {

diff --git a/src/server/services/wms/qgswmsrenderer.cpp b/src/server/services/wms/qgswmsrenderer.cpp
@@ -1096,7 +1096,9 @@ namespace QgsWms
     }
 
     mapSettings.setOutputSize( QSize( paintDevice->width(), paintDevice->height() ) );
-    mapSettings.setOutputDpi( paintDevice->logicalDpiX() );
+    // Recalculate from input DPI: do not take the (integer) value from paint device
+    // because it loose precision!
+    mapSettings.setOutputDpi( mContext.dotsPerMm() * 25.4 );
 
     //map extent
     QgsRectangle mapExtent = mWmsParameters.bboxAsRectangle();

diff --git a/...llimeter/WMS_GetLegendGraphic_ScaleSymbol_DefaultMapUnitsPerMillimeter_mask.png b/...llimeter/WMS_GetLegendGraphic_ScaleSymbol_DefaultMapUnitsPerMillimeter_mask.png
diff --git a/...imeter/WMS_GetLegendGraphic_ScaleSymbol_DefaultMapUnitsPerMillimeter_result.png b/...imeter/WMS_GetLegendGraphic_ScaleSymbol_DefaultMapUnitsPerMillimeter_result.png
diff --git a/...l_DefaultScale_2056/WMS_GetLegendGraphic_ScaleSymbol_DefaultScale_2056_mask.png b/...l_DefaultScale_2056/WMS_GetLegendGraphic_ScaleSymbol_DefaultScale_2056_mask.png
diff --git a/...ntrol_images/qgis_server/WMS_GetMap_Annotations/WMS_GetMap_Annotations_mask.png b/...ntrol_images/qgis_server/WMS_GetMap_Annotations/WMS_GetMap_Annotations_mask.png
diff --git a/...control_images/qgis_server/WMS_GetMap_Background/WMS_GetMap_Background_mask.png b/...control_images/qgis_server/WMS_GetMap_Background/WMS_GetMap_Background_mask.png
diff --git a/...images/qgis_server/WMS_GetMap_Background_Hex/WMS_GetMap_Background_Hex_mask.png b/...images/qgis_server/WMS_GetMap_Background_Hex/WMS_GetMap_Background_Hex_mask.png
diff --git a/.../testdata/control_images/qgis_server/WMS_GetMap_Basic/WMS_GetMap_Basic_mask.png b/.../testdata/control_images/qgis_server/WMS_GetMap_Basic/WMS_GetMap_Basic_mask.png
diff --git a/...estdata/control_images/qgis_server/WMS_GetMap_Basic2/WMS_GetMap_Basic2_mask.png b/...estdata/control_images/qgis_server/WMS_GetMap_Basic2/WMS_GetMap_Basic2_mask.png
diff --git a/...estdata/control_images/qgis_server/WMS_GetMap_Basic3/WMS_GetMap_Basic3_mask.png b/...estdata/control_images/qgis_server/WMS_GetMap_Basic3/WMS_GetMap_Basic3_mask.png
diff --git a/...estdata/control_images/qgis_server/WMS_GetMap_Basic4/WMS_GetMap_Basic4_mask.png b/...estdata/control_images/qgis_server/WMS_GetMap_Basic4/WMS_GetMap_Basic4_mask.png
diff --git a/...estdata/control_images/qgis_server/WMS_GetMap_Basic5/WMS_GetMap_Basic5_mask.png b/...estdata/control_images/qgis_server/WMS_GetMap_Basic5/WMS_GetMap_Basic5_mask.png
diff --git a/...es/qgis_server/WMS_GetMap_ContextRendering/WMS_GetMap_ContextRendering_mask.png b/...es/qgis_server/WMS_GetMap_ContextRendering/WMS_GetMap_ContextRendering_mask.png
diff --git a/...ata/control_images/qgis_server/WMS_GetMap_Diagrams/WMS_GetMap_Diagrams_mask.png b/...ata/control_images/qgis_server/WMS_GetMap_Diagrams/WMS_GetMap_Diagrams_mask.png
diff --git a/...rver/WMS_GetMap_Dimension_All_NoValue/WMS_GetMap_Dimension_All_NoValue_mask.png b/...rver/WMS_GetMap_Dimension_All_NoValue/WMS_GetMap_Dimension_All_NoValue_mask.png
diff --git a/...Dimension_Elevation_MixValues/WMS_GetMap_Dimension_Elevation_MixValues_mask.png b/...Dimension_Elevation_MixValues/WMS_GetMap_Dimension_Elevation_MixValues_mask.png
diff --git a/...nsion_Elevation_MultiValues/WMS_GetMap_Dimension_Elevation_MultiValues_mask.png b/...nsion_Elevation_MultiValues/WMS_GetMap_Dimension_Elevation_MultiValues_mask.png
diff --git a/...mension_Elevation_RangeValue/WMS_GetMap_Dimension_Elevation_RangeValue_mask.png b/...mension_Elevation_RangeValue/WMS_GetMap_Dimension_Elevation_RangeValue_mask.png
diff --git a/...ion_RangeValue_Filter/WMS_GetMap_Dimension_Elevation_RangeValue_Filter_mask.png b/...ion_RangeValue_Filter/WMS_GetMap_Dimension_Elevation_RangeValue_Filter_mask.png
diff --git a/..._GetMap_Dimension_Elevation_Value/WMS_GetMap_Dimension_Elevation_Value_mask.png b/..._GetMap_Dimension_Elevation_Value/WMS_GetMap_Dimension_Elevation_Value_mask.png
diff --git a/...estdata/control_images/qgis_server/WMS_GetMap_Filter/WMS_GetMap_Filter_mask.png b/...estdata/control_images/qgis_server/WMS_GetMap_Filter/WMS_GetMap_Filter_mask.png
diff --git a/...tdata/control_images/qgis_server/WMS_GetMap_Filter2/WMS_GetMap_Filter2_mask.png b/...tdata/control_images/qgis_server/WMS_GetMap_Filter2/WMS_GetMap_Filter2_mask.png
diff --git a/...tdata/control_images/qgis_server/WMS_GetMap_Filter3/WMS_GetMap_Filter3_mask.png b/...tdata/control_images/qgis_server/WMS_GetMap_Filter3/WMS_GetMap_Filter3_mask.png
diff --git a/...tdata/control_images/qgis_server/WMS_GetMap_Filter4/WMS_GetMap_Filter4_mask.png b/...tdata/control_images/qgis_server/WMS_GetMap_Filter4/WMS_GetMap_Filter4_mask.png
diff --git a/...control_images/qgis_server/WMS_GetMap_Filter_OGC/WMS_GetMap_Filter_OGC_mask.png b/...control_images/qgis_server/WMS_GetMap_Filter_OGC/WMS_GetMap_Filter_OGC_mask.png
diff --git a/...ntrol_images/qgis_server/WMS_GetMap_Filter_OGC2/WMS_GetMap_Filter_OGC2_mask.png b/...ntrol_images/qgis_server/WMS_GetMap_Filter_OGC2/WMS_GetMap_Filter_OGC2_mask.png
diff --git a/...ntrol_images/qgis_server/WMS_GetMap_Filter_OGC3/WMS_GetMap_Filter_OGC3_mask.png b/...ntrol_images/qgis_server/WMS_GetMap_Filter_OGC3/WMS_GetMap_Filter_OGC3_mask.png
diff --git a/...l_images/qgis_server/WMS_GetMap_Filter_OGC_V2/WMS_GetMap_Filter_OGC_V2_mask.png b/...l_images/qgis_server/WMS_GetMap_Filter_OGC_V2/WMS_GetMap_Filter_OGC_V2_mask.png
diff --git a/...a/control_images/qgis_server/WMS_GetMap_Highlight/WMS_GetMap_Highlight_mask.png b/...a/control_images/qgis_server/WMS_GetMap_Highlight/WMS_GetMap_Highlight_mask.png
diff --git a/...images/qgis_server/WMS_GetMap_Highlight_Line/WMS_GetMap_Highlight_Line_mask.png b/...images/qgis_server/WMS_GetMap_Highlight_Line/WMS_GetMap_Highlight_Line_mask.png
diff --git a/...ages/qgis_server/WMS_GetMap_Highlight_Point/WMS_GetMap_Highlight_Point_mask.png b/...ages/qgis_server/WMS_GetMap_Highlight_Point/WMS_GetMap_Highlight_Point_mask.png
diff --git a/..._images/qgis_server/WMS_GetMap_LabelingSettings/WMS_GetMap_LabelingSettings.png b/..._images/qgis_server/WMS_GetMap_LabelingSettings/WMS_GetMap_LabelingSettings.png
diff --git a/...es/qgis_server/WMS_GetMap_LabelingSettings/WMS_GetMap_LabelingSettings_mask.png b/...es/qgis_server/WMS_GetMap_LabelingSettings/WMS_GetMap_LabelingSettings_mask.png
diff --git a/...es/qgis_server/WMS_GetMap_Labeling_Complex/WMS_GetMap_Labeling_Complex_mask.png b/...es/qgis_server/WMS_GetMap_Labeling_Complex/WMS_GetMap_Labeling_Complex_mask.png
diff --git a/...control_images/qgis_server/WMS_GetMap_LayerOrder/WMS_GetMap_LayerOrder_mask.png b/...control_images/qgis_server/WMS_GetMap_LayerOrder/WMS_GetMap_LayerOrder_mask.png
diff --git a/...a/control_images/qgis_server/WMS_GetMap_Opacities/WMS_GetMap_Opacities_mask.png b/...a/control_images/qgis_server/WMS_GetMap_Opacities/WMS_GetMap_Opacities_mask.png
diff --git a/...control_images/qgis_server/WMS_GetMap_Opacities2/WMS_GetMap_Opacities2_mask.png b/...control_images/qgis_server/WMS_GetMap_Opacities2/WMS_GetMap_Opacities2_mask.png
diff --git a/...control_images/qgis_server/WMS_GetMap_Opacities3/WMS_GetMap_Opacities3_mask.png b/...control_images/qgis_server/WMS_GetMap_Opacities3/WMS_GetMap_Opacities3_mask.png
diff --git a/...ntrol_images/qgis_server/WMS_GetMap_SLDRestored/WMS_GetMap_SLDRestored_mask.png b/...ntrol_images/qgis_server/WMS_GetMap_SLDRestored/WMS_GetMap_SLDRestored_mask.png
diff --git a/tests/testdata/control_images/qgis_server/WMS_GetMap_SRS/WMS_GetMap_SRS_mask.png b/tests/testdata/control_images/qgis_server/WMS_GetMap_SRS/WMS_GetMap_SRS_mask.png
diff --git a/...a/control_images/qgis_server/WMS_GetMap_Selection/WMS_GetMap_Selection_mask.png b/...a/control_images/qgis_server/WMS_GetMap_Selection/WMS_GetMap_Selection_mask.png
diff --git a/...ntrol_images/qgis_server/WMS_GetMap_StyleCustom/WMS_GetMap_StyleCustom_mask.png b/...ntrol_images/qgis_server/WMS_GetMap_StyleCustom/WMS_GetMap_StyleCustom_mask.png
diff --git a/...rol_images/qgis_server/WMS_GetMap_StyleDefault/WMS_GetMap_StyleDefault_mask.png b/...rol_images/qgis_server/WMS_GetMap_StyleDefault/WMS_GetMap_StyleDefault_mask.png
diff --git a/...control_images/qgis_server/WMS_GetMap_StyleMixed/WMS_GetMap_StyleMixed_mask.png b/...control_images/qgis_server/WMS_GetMap_StyleMixed/WMS_GetMap_StyleMixed_mask.png
diff --git a/...rver/WMS_GetMap_StyleMixed_LayerOrder/WMS_GetMap_StyleMixed_LayerOrder_mask.png b/...rver/WMS_GetMap_StyleMixed_LayerOrder/WMS_GetMap_StyleMixed_LayerOrder_mask.png
diff --git a/...ta/control_images/qgis_server/WMS_GetMap_Transparent/WMS_GetMap_Transparent.png b/...ta/control_images/qgis_server/WMS_GetMap_Transparent/WMS_GetMap_Transparent.png
diff --git a/...estdata/control_images/qgis_server_accesscontrol/WMS_GetMap/WMS_GetMap_mask.png b/...estdata/control_images/qgis_server_accesscontrol/WMS_GetMap/WMS_GetMap_mask.png
diff --git a/..._accesscontrol/WMS_GetMap_projectsubstring/WMS_GetMap_projectsubstring_mask.png b/..._accesscontrol/WMS_GetMap_projectsubstring/WMS_GetMap_projectsubstring_mask.png