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Diffstat (limited to 'src/plugins/qmldesigner/components/curveeditor/detail/axis.cpp')
| -rw-r--r-- | src/plugins/qmldesigner/components/curveeditor/detail/axis.cpp | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/src/plugins/qmldesigner/components/curveeditor/detail/axis.cpp b/src/plugins/qmldesigner/components/curveeditor/detail/axis.cpp new file mode 100644 index 0000000000..6e18e49a26 --- /dev/null +++ b/src/plugins/qmldesigner/components/curveeditor/detail/axis.cpp @@ -0,0 +1,213 @@ +/**************************************************************************** +** +** Copyright (C) 2020 The Qt Company Ltd. +** Contact: https://www.qt.io/licensing/ +** +** This file is part of the Qt Design Tooling +** +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3 as published by the Free Software +** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-3.0.html. +** +****************************************************************************/ +#include "axis.h" + +#include <algorithm> +#include <assert.h> +#include <cmath> +#include <limits> + +namespace DesignTools { + +// The following is based on: "An Extension of Wilkinson's Algorithm for Positioning Tick Labels on Axes" +// by Justin Talbot, Sharon Lin and Pat Hanrahan. +// The Implementation uses the conventions and variable names found in the paper where: +// Inputs: +// Q Preference ordered list of nice steps +// dmin/dmax Data range +// pt Target label density +// fst Target font size (currently ignored) +// Formats set of label formats (currently ignored) +// Other: +// q Element of Q +// i Index of q in Q +// j Label skipping amount (taking only jth label into account) +// lmin/lmax Labeling sequence range +// v Indicator if labeling should include 0. (1 means yes / 0 no) + +double simplicity(int i, std::vector<double> &Q, int j, int v = 1) +{ + assert(Q.size() > 1); + return 1.0 - ((static_cast<double>(i) - 1.0) / (static_cast<double>(Q.size()) - 1.0)) + - static_cast<double>(j) + static_cast<double>(v); +} + +double coverage(double dmin, double dmax, double lmin, double lmax) +{ + return 1.0 - 0.5 * + ((std::pow(dmax - lmax, 2.0) + std::pow(dmin - lmin, 2.0)) / + (std::pow(0.1 * (dmax - dmin), 2.0))); +} + +double coverageMax(double dmin, double dmax, double labelingRange) +{ + double dataRange = dmax - dmin; + if (labelingRange > dataRange) { + double range = (labelingRange - dataRange) / 2.; + return 1 - 0.5 * ((std::pow(range, 2.0) * 2.0) / (std::pow(0.1 * (dmax - dmin), 2.0))); + } + return 1; +} + +double density(double p, double pt) +{ + return 2.0 - std::max(p / pt, pt / p); +} + +double densityMax(double p, double pt) +{ + if (p >= pt) + return 2 - p / pt; + else + return 1; +} + +namespace Legibility { + +class Format +{ +public: + double legibility() const { return 1.0; } +}; + +class FontSize +{ +public: + double legibility() const { return 1.0; } +}; + +class Orientation +{ +public: + double legibility() const { return 1.0; } +}; + +class Overlap +{ +public: + double legibility() const { return 1.0; } +}; + +} // End namespace Legibility. + +using namespace Legibility; + +double legibility(const Format &fmt, const FontSize &fs, const Orientation &ori, const Overlap &ovl) +{ + return (fmt.legibility() + fs.legibility() + ori.legibility() + ovl.legibility()) / 4.0; +} + +struct LabelingInfo +{ + double l; + Format lformat; +}; + +LabelingInfo optLegibility(int k, double lmin, double lstep) +{ + std::vector<double> stepSequence; + for (int i = 0; i < k; ++i) + stepSequence.push_back(lmin + i * lstep); + + Format fmt; + FontSize fs; + Orientation ori; + Overlap ovl; + + LabelingInfo info; + info.l = legibility(fmt, fs, ori, ovl); + info.lformat = fmt; + return info; +} + +Axis Axis::compute(double dmin, double dmax, double height, double pt) +{ + Axis result = {0.0, 0.0, 0.0}; + + auto score = [](double a, double b, double c, double d) { + return a * 0.2 + b * 0.25 + c * 0.5 + d * 0.05; + }; + + std::vector<double> Q = {1., 5., 2., 2.5, 3.}; + //std::vector<double> Q = {1., 5., 2., 2.5, 3., 4., 1.5, 7., 6., 8., 9.}; + + double best_score = -2.0; + int j = 1; + while (j < std::numeric_limits<int>::max()) { + for (int i = 0; i < static_cast<int>(Q.size()); ++i) { + double q = Q[i]; + + auto simMax = simplicity(i, Q, j); + if (score(simMax, 1.0, 1.0, 1.0) < best_score) { + j = std::numeric_limits<int>::max() - 1; + break; + } + + int k = 2; // label count + while (k < std::numeric_limits<int>::max()) { + auto p = k / height; + auto denMax = densityMax(p, pt); + if (score(simMax, 1.0, denMax, 1.0) < best_score) + break; + + auto delta = (dmax - dmin) / (k + 1) / (j * q); + int z = std::ceil(std::log10(delta)); + while (z < std::numeric_limits<int>::max()) { + auto lstep = q * static_cast<double>(j) * std::pow(10, z); + auto covMax = coverageMax(dmin, dmax, lstep * (k - 1)); + if (score(simMax, covMax, denMax, 1.0) < best_score) + break; + + int start = (std::floor(dmax / lstep) - (k - 1)) * j; + int end = std::ceil(dmin / lstep) * j; + for (; start <= end; ++start) { + double lmin = start * lstep / j; + double lmax = lmin + lstep * (k - 1); + + double s = simplicity(i, Q, j); + double d = density(p, pt); + double c = coverage(dmin, dmax, lmin, lmax); + + if (score(s, c, d, 1.0) < best_score) + continue; + + auto info = optLegibility(k, lmin, lstep); + const double cscore = score(s, c, d, info.l); + if (cscore > best_score) { + best_score = cscore; + result = {lmin, lmax, lstep}; + } + } + z++; + } + k++; + } + } + j++; + } + return result; +} + +} // End namespace DesignTools. |