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| // | |
| // HtmlUtils.h | |
| // | |
| // Created on: Jun 8, 2011 | |
| // Author: Joshua Richardson <[email protected]> | |
| // Copyright 2011 | |
| // | |
| // All changes made under the Poppler project to this file are licensed | |
| // under GPL version 2 or later | |
| // | |
| // Copyright (C) 2011 Joshua Richardson <[email protected]> | |
| // | |
| // To see a description of the changes please see the Changelog file that | |
| // came with your tarball or type make ChangeLog if you are building from git | |
| // | |
| //======================================================================== | |
| // Returns true iff the difference between a and b is less than the threshold | |
| // We always use fuzzy math when comparing decimal numbers due to imprecision | |
| inline bool is_within(double a, double thresh, double b) | |
| { | |
| return fabs(a - b) < thresh; | |
| } | |
| inline bool rot_matrices_equal(const double *const mat0, const double *const mat1) | |
| { | |
| return is_within(mat0[0], .1, mat1[0]) && is_within(mat0[1], .1, mat1[1]) && is_within(mat0[2], .1, mat1[2]) && is_within(mat0[3], .1, mat1[3]); | |
| } | |
| // rotation is (cos q, sin q, -sin q, cos q, 0, 0) | |
| // sin q is zero iff there is no rotation, or 180 deg. rotation; | |
| // for 180 rotation, cos q will be negative | |
| inline bool isMatRotOrSkew(const double *const mat) | |
| { | |
| return mat[0] < 0 || !is_within(mat[1], .1, 0); | |
| } | |
| // Alters the matrix so that it does not scale a vector's x component; | |
| // If the matrix does not skew, then that will also normalize the y | |
| // component, keeping any rotation, but removing scaling. | |
| inline void normalizeRotMat(double *mat) | |
| { | |
| double scale = fabs(mat[0] + mat[1]); | |
| if (!scale) { | |
| return; | |
| } | |
| for (int i = 0; i < 4; i++) { | |
| mat[i] /= scale; | |
| } | |
| } | |