LibGFX/PAM: Allow reading CMYK .pam files

These are written by `mutool extract` for CMYK images.

They don't contain color profiles so they're not super convenient.
But `image` can convert them (*) to sRGB as long as you use it with
`--assign-color-profile` pointing to some CMYK icc profile of your
choice.

*: Once #22922 is merged.
This commit is contained in:
Nico Weber 2024-01-24 21:51:22 -05:00 committed by Andreas Kling
parent 187862ebe0
commit 556addc5cb
3 changed files with 70 additions and 18 deletions

View file

@ -19,30 +19,41 @@ ErrorOr<void> read_image_data(PAMLoadingContext& context)
bool is_rgb = context.format_details.depth == 3 && context.format_details.tupl_type == "RGB"sv;
bool is_rgba = context.format_details.depth == 4 && context.format_details.tupl_type == "RGB_ALPHA"sv;
if (!is_gray && !is_gray_alpha && !is_rgb && !is_rgba)
return Error::from_string_view("Unsupported PAM depth"sv);
bool is_cmyk = context.format_details.depth == 4 && context.format_details.tupl_type == "CMYK"sv;
TRY(create_bitmap(context));
if (!is_gray && !is_gray_alpha && !is_rgb && !is_rgba && !is_cmyk)
return Error::from_string_view("Unsupported PAM depth"sv);
auto& stream = *context.stream;
for (u64 i = 0; i < context.width * context.height; ++i) {
if (is_gray) {
Array<u8, 1> pixel;
TRY(stream.read_until_filled(pixel));
context.bitmap->set_pixel(i % context.width, i / context.width, { pixel[0], pixel[0], pixel[0] });
} else if (is_gray_alpha) {
Array<u8, 2> pixel;
TRY(stream.read_until_filled(pixel));
context.bitmap->set_pixel(i % context.width, i / context.width, { pixel[0], pixel[0], pixel[0], pixel[1] });
} else if (is_rgb) {
Array<u8, 3> pixel;
TRY(stream.read_until_filled(pixel));
context.bitmap->set_pixel(i % context.width, i / context.width, { pixel[0], pixel[1], pixel[2] });
} else if (is_rgba) {
if (is_cmyk) {
context.format_details.cmyk_bitmap = TRY(CMYKBitmap::create_with_size({ context.width, context.height }));
CMYK* data = context.format_details.cmyk_bitmap.value()->begin();
for (u64 i = 0; i < context.width * context.height; ++i) {
Array<u8, 4> pixel;
TRY(stream.read_until_filled(pixel));
context.bitmap->set_pixel(i % context.width, i / context.width, { pixel[0], pixel[1], pixel[2], pixel[3] });
data[i] = { pixel[0], pixel[1], pixel[2], pixel[3] };
}
} else {
TRY(create_bitmap(context));
for (u64 i = 0; i < context.width * context.height; ++i) {
if (is_gray) {
Array<u8, 1> pixel;
TRY(stream.read_until_filled(pixel));
context.bitmap->set_pixel(i % context.width, i / context.width, { pixel[0], pixel[0], pixel[0] });
} else if (is_gray_alpha) {
Array<u8, 2> pixel;
TRY(stream.read_until_filled(pixel));
context.bitmap->set_pixel(i % context.width, i / context.width, { pixel[0], pixel[0], pixel[0], pixel[1] });
} else if (is_rgb) {
Array<u8, 3> pixel;
TRY(stream.read_until_filled(pixel));
context.bitmap->set_pixel(i % context.width, i / context.width, { pixel[0], pixel[1], pixel[2] });
} else if (is_rgba) {
Array<u8, 4> pixel;
TRY(stream.read_until_filled(pixel));
context.bitmap->set_pixel(i % context.width, i / context.width, { pixel[0], pixel[1], pixel[2], pixel[3] });
}
}
}

View file

@ -18,6 +18,7 @@ struct PAM {
u16 max_val { 0 };
u16 depth { 0 };
String tupl_type {};
Optional<NonnullRefPtr<CMYKBitmap>> cmyk_bitmap {};
};
using PAMLoadingContext = PortableImageMapLoadingContext<PAM>;

View file

@ -62,6 +62,9 @@ public:
virtual ErrorOr<ImageFrameDescriptor> frame(size_t index, Optional<IntSize> ideal_size = {}) override;
virtual NaturalFrameFormat natural_frame_format() const override;
virtual ErrorOr<NonnullRefPtr<CMYKBitmap>> cmyk_frame() override;
private:
PortableImageDecoderPlugin(NonnullOwnPtr<SeekableStream> stream);
@ -126,8 +129,45 @@ ErrorOr<ImageFrameDescriptor> PortableImageDecoderPlugin<TContext>::frame(size_t
}
}
if constexpr (requires { TContext::FormatDetails::cmyk_bitmap; }) {
if (m_context->format_details.cmyk_bitmap.has_value())
m_context->bitmap = TRY(m_context->format_details.cmyk_bitmap.value()->to_low_quality_rgb());
}
VERIFY(m_context->bitmap);
return ImageFrameDescriptor { m_context->bitmap, 0 };
}
template<typename TContext>
NaturalFrameFormat PortableImageDecoderPlugin<TContext>::natural_frame_format() const
{
if constexpr (requires { TContext::FormatDetails::cmyk_bitmap; }) {
if (m_context->format_details.depth == 4 && m_context->format_details.tupl_type == "CMYK"sv)
return NaturalFrameFormat::CMYK;
}
return NaturalFrameFormat::RGB;
}
template<typename TContext>
ErrorOr<NonnullRefPtr<CMYKBitmap>> PortableImageDecoderPlugin<TContext>::cmyk_frame()
{
if constexpr (requires { TContext::FormatDetails::cmyk_bitmap; }) {
VERIFY(natural_frame_format() == NaturalFrameFormat::CMYK);
if (m_context->state == TContext::State::Error)
return Error::from_string_literal("PortableImageDecoderPlugin: Decoding failed");
if (m_context->state < TContext::State::BitmapDecoded) {
if (decode(*m_context).is_error()) {
m_context->state = TContext::State::Error;
return Error::from_string_literal("PortableImageDecoderPlugin: Decoding failed");
}
}
return *m_context->format_details.cmyk_bitmap.value();
}
VERIFY_NOT_REACHED();
}
}