92 lines
2.4 KiB
C++
92 lines
2.4 KiB
C++
#pragma once
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#include <BAN/Limits.h>
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#include <BAN/StringView.h>
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#include <BAN/UniqPtr.h>
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#include <BAN/Vector.h>
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namespace LibImage
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{
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class Image
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{
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public:
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struct Color
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{
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uint8_t r;
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uint8_t g;
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uint8_t b;
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uint8_t a;
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// Calculate weighted average of colors
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// weight of 0.0 returns a and weight of 1.0 returns b
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static Color average(Color a, Color b, double weight)
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{
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const double b_mult = BAN::Math::clamp(weight, 0.0, 1.0);
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const double a_mult = 1.0 - b_mult;
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return Color {
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.r = static_cast<uint8_t>(a.r * a_mult + b.r * b_mult),
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.g = static_cast<uint8_t>(a.g * a_mult + b.g * b_mult),
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.b = static_cast<uint8_t>(a.b * a_mult + b.b * b_mult),
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.a = static_cast<uint8_t>(a.a * a_mult + b.a * b_mult),
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};
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}
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uint32_t as_rgba() const
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{
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return ((uint32_t)a << 24) | ((uint32_t)r << 16) | ((uint32_t)g << 8) | b;
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}
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};
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enum class ResizeAlgorithm
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{
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Nearest,
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Linear,
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Cubic,
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};
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public:
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static BAN::ErrorOr<BAN::UniqPtr<Image>> load_from_file(BAN::StringView path);
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BAN::ErrorOr<BAN::UniqPtr<Image>> resize(uint64_t new_width, uint64_t new_height, ResizeAlgorithm = ResizeAlgorithm::Cubic);
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Color get_color(uint64_t x, uint64_t y) const { return m_bitmap[y * width() + x]; }
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const BAN::Vector<Color> bitmap() const { return m_bitmap; }
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uint64_t width() const { return m_width; }
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uint64_t height() const { return m_height; }
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static constexpr bool validate_size(uint64_t width, uint64_t height)
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{
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// width and height must fit in int64_t and width * height * sizeof(Color) has to not overflow
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if (width > static_cast<uint64_t>(BAN::numeric_limits<int64_t>::max()))
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return false;
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if (height > static_cast<uint64_t>(BAN::numeric_limits<int64_t>::max()))
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return false;
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if (BAN::Math::will_multiplication_overflow<uint64_t>(width, height))
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return false;
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if (BAN::Math::will_multiplication_overflow<uint64_t>(width * height, sizeof(Color)))
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return false;
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return true;
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}
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private:
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Image(uint64_t width, uint64_t height, BAN::Vector<Color>&& bitmap)
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: m_width(width)
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, m_height(height)
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, m_bitmap(BAN::move(bitmap))
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{
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ASSERT(validate_size(m_width, m_height));
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ASSERT(m_bitmap.size() >= m_width * m_height);
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}
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private:
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const uint64_t m_width;
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const uint64_t m_height;
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const BAN::Vector<Color> m_bitmap;
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friend class BAN::UniqPtr<Image>;
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};
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}
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