From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Mon, 23 Jan 2012 11:28:16 +0000 (+0000)
Subject: Fix wxAffineMatrix2D::Translate() to multiply on the left.
X-Git-Url: https://git.saurik.com/wxWidgets.git/commitdiff_plain/5c7fe477625af2c6802f9c4f165ab02a304d109d

Fix wxAffineMatrix2D::Translate() to multiply on the left.

The affine transform was previously multiplied by the translation matrix on
the right but this was incompatible with both the MSW version of the same
method and all the other methods of the generic version.

So multiply the transform by the translation on the left, as everywhere else.

Closes #13875.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70444 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
---

diff --git a/src/common/affinematrix2d.cpp b/src/common/affinematrix2d.cpp
index 5df1bac1e6..0b1b9207dc 100644
--- a/src/common/affinematrix2d.cpp
+++ b/src/common/affinematrix2d.cpp
@@ -106,10 +106,13 @@ bool wxAffineMatrix2D::IsEqual(const wxAffineMatrix2DBase& t) const
 //
 
 // add the translation to this matrix
+// |  1   0   0 |   | m_11  m_12   0 |
+// |  0   1   0 | x | m_21  m_22   0 |
+// | dx  dy   1 |   | m_tx  m_ty   1 |
 void wxAffineMatrix2D::Translate(wxDouble dx, wxDouble dy)
 {
-    m_tx += dx;
-    m_ty += dy;
+    m_tx += m_11 * dx + m_21 * dy;
+    m_ty += m_12 * dx + m_22 * dy;
 }
 
 // add the scale to this matrix
diff --git a/tests/graphics/affinematrix.cpp b/tests/graphics/affinematrix.cpp
index ee6c5470dd..90f56cc1a9 100644
--- a/tests/graphics/affinematrix.cpp
+++ b/tests/graphics/affinematrix.cpp
@@ -112,7 +112,7 @@ void AffineTransformTestCase::VMirrorAndTranslate()
 
         wxAffineMatrix2D matrix;
         matrix.Mirror(wxVERTICAL);
-        matrix.Translate(0, m_bmpOrig.GetHeight() - 1);
+        matrix.Translate(0, -m_bmpOrig.GetHeight() + 1);
         dc.SetTransformMatrix(matrix);
         dc.DrawBitmap(m_bmpOrig, 0, 0);
     }
@@ -134,7 +134,7 @@ void AffineTransformTestCase::Rotate90Clockwise()
 
         wxAffineMatrix2D matrix;
         matrix.Rotate(-0.5 * M_PI);
-        matrix.Translate(m_bmpOrig.GetHeight(), 0);
+        matrix.Translate(0, -m_bmpOrig.GetHeight());
         dc.SetTransformMatrix(matrix);
         dc.DrawBitmap(m_bmpOrig, 0, 0);
     }