diff --git a/src/transf_mat_3x4.cpp b/src/transf_mat_3x4.cpp
index b7cd278d4febfdf28b665b89629655843bcdb180..6b49dc44aa70a8f6cdaf41a0156202721ae833bc 100644 (file)
--- a/src/transf_mat_3x4.cpp
+++ b/src/transf_mat_3x4.cpp
return g_strdup(os.str().c_str());
}
+/* Check for equality (with a small tolerance epsilon) */
bool
TransfMat3x4::operator==(const TransfMat3x4 &rhs) const
{
return true;
}
-/* multiply a projective matrix by an affine matrix */
+/* Multiply a projective matrix by an affine matrix (by only multiplying the 'affine part' of the
+ * projective matrix) */
TransfMat3x4
TransfMat3x4::operator*(Geom::Matrix const &A) const {
TransfMat3x4 ret;
- // Is it safe to always use the currently active document?
- double h = sp_document_height(inkscape_active_document());
-
- /*
- * Note: The strange multiplication involving the document height is due to the buggy
- * intertwining of SVG and document coordinates. Essentially, what we do is first
- * convert from "real-world" to SVG coordinates, then apply the transformation A
- * (by multiplying with the Geom::Matrix) and then convert back from SVG to real-world
- * coordinates. Maybe there is even a more Inkscape-ish way to achieve this?
- * Once Inkscape has gotton rid of the two different coordiate systems, we can change
- * this function to an ordinary matrix multiplication.
- */
for (int j = 0; j < 4; ++j) {
- ret.tmat[0][j] = A[0]*tmat[0][j] + A[2]*(h*tmat[2][j] - tmat[1][j]) + A[4]*tmat[2][j];
- ret.tmat[1][j] = A[1]*tmat[0][j] + A[3]*(h*tmat[2][j] - tmat[1][j]) + A[5]*tmat[2][j];
+ ret.tmat[0][j] = A[0]*tmat[0][j] + A[2]*tmat[1][j] + A[4]*tmat[2][j];
+ ret.tmat[1][j] = A[1]*tmat[0][j] + A[3]*tmat[1][j] + A[5]*tmat[2][j];
ret.tmat[2][j] = tmat[2][j];
-
- ret.tmat[1][j] = h*ret.tmat[2][j] - ret.tmat[1][j]; // switch back from SVG to desktop coordinates
}
return ret;