font_metrics.h

/*
**  UICore
**  Copyright (c) 1997-2015 The UICore Team
**
**  This software is provided 'as-is', without any express or implied
**  warranty.  In no event will the authors be held liable for any damages
**  arising from the use of this software.
**
**  Permission is granted to anyone to use this software for any purpose,
**  including commercial applications, and to alter it and redistribute it
**  freely, subject to the following restrictions:
**
**  1. The origin of this software must not be misrepresented; you must not
**     claim that you wrote the original software. If you use this software
**     in a product, an acknowledgment in the product documentation would be
**     appreciated but is not required.
**  2. Altered source versions must be plainly marked as such, and must not be
**     misrepresented as being the original software.
**  3. This notice may not be removed or altered from any source distribution.
**
**  Note: Some of the libraries UICore may link to may have additional
**  requirements or restrictions.
**
**  File Author(s):
**
**    Magnus Norddahl
**    Harry Storbacka
**    Mark Page
*/

#pragma once

#include <memory>
#include <cmath>

namespace uicore
{
    class FontMetrics
    {
    public:
        // \brief Text metrics constructor
        // \param line_height If 0, then line_height is calculated as height + external_leading
        FontMetrics() { }
        FontMetrics(float height, float ascent, float descent, float internal_leading, float external_leading, float line_height, float pixel_ratio)
            : _height(height), _ascent(ascent), _descent(descent), _internal_leading(internal_leading), _external_leading(external_leading), _line_height(line_height)
        {
            // Calculate line_height when not specified
            if (_line_height == 0.0f)
                _line_height = height + external_leading;

            _baseline_offset = (_line_height - _height) * 0.5f + ascent;
            _baseline_offset = std::round(_baseline_offset / pixel_ratio) * pixel_ratio;
        }

        float height() const { return _height; }

        float line_height() const { return _line_height; }

        float baseline_offset() const { return _baseline_offset; }

        float ascent() const { return _ascent; }

        float descent() const { return _descent; }

        float internal_leading() const { return _internal_leading; }

        float external_leading() const { return _external_leading; }

    private:
        float _height = 0.0f;
        float _ascent = 0.0f;
        float _descent = 0.0f;
        float _internal_leading = 0.0f;
        float _external_leading = 0.0f;
        float _line_height = 0.0f;
        float _baseline_offset = 0.0f;
    };
}