banan-os/LibImage/Image.cpp

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#include <BAN/ScopeGuard.h>
#include <BAN/String.h>
#include <LibImage/Image.h>
#include <LibImage/Netbpm.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/mman.h>
namespace LibImage
{
BAN::ErrorOr<BAN::UniqPtr<Image>> Image::load_from_file(BAN::StringView path)
{
int fd = -1;
if (path.data()[path.size()] == '\0')
{
fd = open(path.data(), O_RDONLY);
}
else
{
BAN::String path_str;
TRY(path_str.append(path));
fd = open(path_str.data(), O_RDONLY);
}
if (fd == -1)
{
fprintf(stddbg, "open: %s\n", strerror(errno));
return BAN::Error::from_errno(errno);
}
BAN::ScopeGuard guard_file_close([fd] { close(fd); });
struct stat st;
if (fstat(fd, &st) == -1)
{
fprintf(stddbg, "fstat: %s\n", strerror(errno));
return BAN::Error::from_errno(errno);
}
if (st.st_size < 2)
{
fprintf(stddbg, "invalid image (too small)\n");
return BAN::Error::from_errno(EINVAL);
}
void* addr = mmap(nullptr, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (addr == MAP_FAILED)
{
fprintf(stddbg, "mmap: %s\n", strerror(errno));
return BAN::Error::from_errno(errno);
}
BAN::ScopeGuard guard_munmap([&] { munmap(addr, st.st_size); });
auto image_data_span = BAN::ConstByteSpan(reinterpret_cast<uint8_t*>(addr), st.st_size);
uint16_t u16_signature = image_data_span.as<const uint16_t>();
switch (u16_signature)
{
case 0x3650:
case 0x3550:
case 0x3450:
case 0x3350:
case 0x3250:
case 0x3150:
return TRY(load_netbpm(image_data_span));
default:
fprintf(stderr, "unrecognized image format\n");
break;
}
return BAN::Error::from_errno(ENOTSUP);
}
BAN::ErrorOr<BAN::UniqPtr<Image>> Image::resize(uint64_t new_width, uint64_t new_height, ResizeAlgorithm algorithm)
{
if (!validate_size(new_width, new_height))
return BAN::Error::from_errno(EOVERFLOW);
const double ratio_x = (double)width() / new_width;
const double ratio_y = (double)height() / new_height;
switch (algorithm)
{
case ResizeAlgorithm::Nearest:
{
BAN::Vector<Color> nearest_bitmap;
TRY(nearest_bitmap.resize(new_width * new_height));
for (uint64_t y = 0; y < new_height; y++)
{
for (uint64_t x = 0; x < new_width; x++)
{
const uint64_t nearest_x = BAN::Math::clamp<uint64_t>(x * ratio_x, 0, width() - 1);
const uint64_t nearest_y = BAN::Math::clamp<uint64_t>(y * ratio_y, 0, height() - 1);
nearest_bitmap[y * new_width + x] = get_color(nearest_x, nearest_y);
}
}
return TRY(BAN::UniqPtr<Image>::create(new_width, new_height, BAN::move(nearest_bitmap)));
}
case ResizeAlgorithm::Bilinear:
{
BAN::Vector<Color> bilinear_bitmap;
TRY(bilinear_bitmap.resize(new_width * new_height));
for (uint64_t y = 0; y < new_height; y++)
{
for (uint64_t x = 0; x < new_width; x++)
{
const double src_x_float = x * ratio_x;
const double src_y_float = y * ratio_y;
const double weight_x = src_x_float - floor(src_x_float);
const double weight_y = src_y_float - floor(src_y_float);
const uint64_t src_l = BAN::Math::clamp<uint64_t>(src_x_float, 0, width() - 1);
const uint64_t src_t = BAN::Math::clamp<uint64_t>(src_y_float, 0, height() - 1);
const uint64_t src_r = BAN::Math::clamp<uint64_t>(src_l + 1, 0, width() - 1);
const uint64_t src_b = BAN::Math::clamp<uint64_t>(src_t + 1, 0, height() - 1);
const Color avg_t = Color::average(get_color(src_l, src_t), get_color(src_r, src_t), weight_x);
const Color avg_b = Color::average(get_color(src_l, src_b), get_color(src_r, src_b), weight_x);
bilinear_bitmap[y * new_width + x] = Color::average(avg_t, avg_b, weight_y);
}
}
return TRY(BAN::UniqPtr<Image>::create(new_width, new_height, BAN::move(bilinear_bitmap)));
}
}
return BAN::Error::from_errno(EINVAL);
}
}