From 409c581f29601382547a7cd3d387518b765364ef Mon Sep 17 00:00:00 2001
From: JP Cimalando <jp-dev@inbox.ru>
Date: Thu, 7 Feb 2019 21:27:59 +0100
Subject: [PATCH] Widget drawing with cairo in local coordinates

---
 dgl/src/WidgetPrivateData.cpp            | 15 +++++++++++++++
 examples/CairoUI/DemoWidgetBanner.cpp    |  8 ++------
 examples/CairoUI/DemoWidgetClickable.cpp | 14 +++++---------
 3 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/dgl/src/WidgetPrivateData.cpp b/dgl/src/WidgetPrivateData.cpp
index fc3da447..005e4960 100644
--- a/dgl/src/WidgetPrivateData.cpp
+++ b/dgl/src/WidgetPrivateData.cpp
@@ -19,6 +19,9 @@
 #ifdef DGL_OPENGL
 # include "../OpenGL.hpp"
 #endif
+#ifdef DGL_CAIRO
+# include "../Cairo.hpp"
+#endif
 
 START_NAMESPACE_DGL
 
@@ -73,6 +76,14 @@ void Widget::PrivateData::display(const uint width,
     }
 #endif
 
+#ifdef DGL_CAIRO
+    cairo_t* cr = parent.getGraphicsContext().cairo;
+    cairo_matrix_t matrix;
+    cairo_get_matrix(cr, &matrix);
+    cairo_translate(cr, absolutePos.getX(), absolutePos.getY());
+    // TODO: scaling with cairo
+#endif
+
     // display widget
     self->onDisplay();
 
@@ -84,6 +95,10 @@ void Widget::PrivateData::display(const uint width,
     }
 #endif
 
+#ifdef DGL_CAIRO
+    cairo_set_matrix(cr, &matrix);
+#endif
+
     displaySubWidgets(width, height, scaling);
 }
 
diff --git a/examples/CairoUI/DemoWidgetBanner.cpp b/examples/CairoUI/DemoWidgetBanner.cpp
index 56a631dd..9835e38a 100644
--- a/examples/CairoUI/DemoWidgetBanner.cpp
+++ b/examples/CairoUI/DemoWidgetBanner.cpp
@@ -59,11 +59,7 @@ void DemoWidgetBanner::onDisplay()
 {
     cairo_t* cr = getParentWindow().getGraphicsContext().cairo;
 
-    Point<int> pt = getAbsolutePos();
     Size<uint> sz = getSize();
-
-    int x = pt.getX();
-    int y = pt.getY();
     int w = sz.getWidth();
     int h = sz.getHeight();
 
@@ -75,8 +71,8 @@ void DemoWidgetBanner::onDisplay()
     {
         for (int c = 0; c < columns; ++c)
         {
-            double cx = x + xoff + radius + c * diameter;
-            double cy = y + yoff + radius + r * diameter;
+            double cx = xoff + radius + c * diameter;
+            double cy = yoff + radius + r * diameter;
 
             char ch = banner[c + r * columns];
             if (ch != ' ')
diff --git a/examples/CairoUI/DemoWidgetClickable.cpp b/examples/CairoUI/DemoWidgetClickable.cpp
index 98ad4d6c..67843ff5 100644
--- a/examples/CairoUI/DemoWidgetClickable.cpp
+++ b/examples/CairoUI/DemoWidgetClickable.cpp
@@ -28,11 +28,7 @@ void DemoWidgetClickable::onDisplay()
 {
     cairo_t* cr = getParentWindow().getGraphicsContext().cairo;
 
-    Point<int> pt = getAbsolutePos();
     Size<uint> sz = getSize();
-
-    int x = pt.getX();
-    int y = pt.getY();
     int w = sz.getWidth();
     int h = sz.getHeight();
 
@@ -48,17 +44,17 @@ void DemoWidgetClickable::onDisplay()
         cairo_set_source_rgb(cr, 0.0, 0.0, 0.75);
         break;
     }
-    cairo_rectangle(cr, x, y, w, h);
+    cairo_rectangle(cr, 0, 0, w, h);
     cairo_fill(cr);
 
     cairo_set_source_rgb(cr, 0.9, 0.9, 0.9);
     cairo_new_path(cr);
-    cairo_move_to(cr, x + 0.25 * w, y + 0.25 * h);
-    cairo_line_to(cr, x + 0.75 * w, y + 0.75 * h);
+    cairo_move_to(cr, 0.25 * w, 0.25 * h);
+    cairo_line_to(cr, 0.75 * w, 0.75 * h);
     cairo_stroke(cr);
     cairo_new_path(cr);
-    cairo_move_to(cr, x + 0.75 * w, y + 0.25 * h);
-    cairo_line_to(cr, x + 0.25 * w, y + 0.75 * h);
+    cairo_move_to(cr, 0.75 * w, 0.25 * h);
+    cairo_line_to(cr, 0.25 * w, 0.75 * h);
     cairo_stroke(cr);
 }