diff options
Diffstat (limited to 'cppcanvas/source/inc/implrenderer.hxx')
| -rw-r--r-- | cppcanvas/source/inc/implrenderer.hxx | 33 |
1 files changed, 23 insertions, 10 deletions
diff --git a/cppcanvas/source/inc/implrenderer.hxx b/cppcanvas/source/inc/implrenderer.hxx index 0b584fad9a85..033882d15620 100644 --- a/cppcanvas/source/inc/implrenderer.hxx +++ b/cppcanvas/source/inc/implrenderer.hxx @@ -76,19 +76,26 @@ namespace cppcanvas }; // EMF+ - // TODO: replace? + // Transformation matrix (used for Affine Transformation) + // [ eM11, eM12, eDx ] + // [ eM21, eM22, eDy ] + // [ 0, 0, 1 ] + // that consists of a linear map (eM11, eM12, eM21, eM22) + // More info: https://en.wikipedia.org/wiki/Linear_map + // followed by a translation (eDx, eDy) + struct XForm { - float eM11; - float eM12; - float eM21; - float eM22; - float eDx; - float eDy; + float eM11; // M1,1 value in the matrix. Increases or decreases the size of the pixels horizontally. + float eM12; // M1,2 value in the matrix. This effectively angles the X axis up or down. + float eM21; // M2,1 value in the matrix. This effectively angles the Y axis left or right. + float eM22; // M2,2 value in the matrix. Increases or decreases the size of the pixels vertically. + float eDx; // Delta x (Dx) value in the matrix. Moves the whole coordinate system horizontally. + float eDy; // Delta y (Dy) value in the matrix. Moves the whole coordinate system vertically. XForm() { SetIdentity (); - }; + } void SetIdentity () { @@ -106,14 +113,20 @@ namespace cppcanvas eDy = f.eDy; } + // Multiple two square matrices + // [ eM11, eM12, eDx ] [ f.eM11, f.eM12, f.eDx ] + // [ eM21, eM22, eDy ] x [ f.eM21, f.eM22, f.eDy ] + // [ 0, 0, 1 ] [ 0, 0, 1 ] + // More information: https://en.wikipedia.org/wiki/Matrix_multiplication#Square_matrices + // FIXME We shouldn't modify source matrix during computation void Multiply (const XForm& f) { eM11 = eM11*f.eM11 + eM12*f.eM21; eM12 = eM11*f.eM12 + eM12*f.eM22; eM21 = eM21*f.eM11 + eM22*f.eM21; eM22 = eM21*f.eM12 + eM22*f.eM22; - eDx *= eDx*f.eM11 + eDy*f.eM21 + f.eDx; - eDy *= eDx*f.eM12 + eDy*f.eM22 + f.eDy; + eDx = eDx*f.eM11 + eDy*f.eM21 + f.eDx; + eDy = eDx*f.eM12 + eDy*f.eM22 + f.eDy; } #ifdef OSL_BIGENDIAN |