fixup TextEditor selection color

src/gui/TextEditor.cpp

@@ -971,8 +971,9 @@ void TextEditor::paint(cairo_t* cr, GdkRectangle* repaintRect, double zoom) {
     bool hasSelection = gtk_text_buffer_get_selection_bounds(this->buffer, &start, &end);
 
     if (hasSelection) {
+        auto selectionColorU16 = Util::GdkRGBA_to_ColorU16(selectionColor);
         PangoAttribute* attrib =
-                pango_attr_background_new(selectionColor.red, selectionColor.green, selectionColor.blue);
+                pango_attr_background_new(selectionColorU16.red, selectionColorU16.green, selectionColorU16.blue);
         PangoAttrList* list = pango_layout_get_attributes(this->layout);
 
         attrib->start_index = getByteOffset(gtk_text_iter_get_offset(&start));
@@ -1010,8 +1011,7 @@ void TextEditor::paint(cairo_t* cr, GdkRectangle* repaintRect, double zoom) {
 
     // set the line always the same size on display
     cairo_set_line_width(cr, 1 / zoom);
-    cairo_set_source_rgb(cr, selectionColor.red / 65536.0, selectionColor.green / 65536.0,
-                         selectionColor.blue / 65536.0);
+    gdk_cairo_set_source_rgba(cr, &selectionColor);
 
     cairo_rectangle(cr, x0 - 5 / zoom, y0 - 5 / zoom, width + 10 / zoom, height + 10 / zoom);
     cairo_stroke(cr);

src/util/Color.h

@@ -17,7 +17,6 @@
 
 #include <gtk/gtk.h>
 
-
 #ifndef XOURNAL_ENFORCE_COLOR
 using Color = uint32_t;
 #else
@@ -84,6 +83,13 @@ struct hash<Color> {
 
 #endif
 
+struct ColorU16 {
+    uint16_t red{};
+    uint16_t green{};
+    uint16_t blue{};
+    uint16_t alpha{};
+};
+
 namespace Util {
 
 constexpr auto rgb_to_GdkRGBA(Color color) -> GdkRGBA;
@@ -92,6 +98,8 @@ constexpr auto argb_to_GdkRGBA(Color color, double alpha) -> GdkRGBA;
 constexpr auto GdkRGBA_to_argb(const GdkRGBA& color) -> Color;
 constexpr auto GdkRGBA_to_rgb(const GdkRGBA& color) -> Color;
 
+constexpr auto GdkRGBA_to_ColorU16(const GdkRGBA& color) -> ColorU16;
+
 
 void cairo_set_source_rgbi(cairo_t* cr, Color color);
 void cairo_set_source_rgbi(cairo_t* cr, Color color, double alpha);
@@ -137,3 +145,16 @@ constexpr auto Util::floatToUIntColor(const double color) -> uint32_t {  //
     static_assert(MAX_COLOR < 256.0, "MAX_COLOR isn't smaller than 256");
     return static_cast<uint32_t>(color * MAX_COLOR);
 }
+
+constexpr auto Util::GdkRGBA_to_ColorU16(const GdkRGBA& color) -> ColorU16 {
+    auto floatToColorU16 = [](double color) {
+        constexpr double MAX_COLOR = 65536.0 - std::numeric_limits<double>::epsilon() * (65536.0 / 2.0);
+        static_assert(MAX_COLOR < 65536.0, "MAX_COLOR isn't smaller than 65536");
+        return static_cast<uint16_t>(color * MAX_COLOR);
+    };
+
+    return {floatToColorU16(color.red),    //
+            floatToColorU16(color.green),  //
+            floatToColorU16(color.blue),   //
+            floatToColorU16(color.alpha)};
+}