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 // // HtmlUtils.h // // Created on: Jun 8, 2011 // Author: Joshua Richardson // 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 // // 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 // //======================================================================== #ifndef HTMLUTILS_H_ #define HTMLUTILS_H_ #include // fabs // 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; } #endif /* HTMLUTILS_H_ */