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LibPDF: Extract a apply_alpha_channel() function

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No behavior change.
This commit is contained in:
Nico Weber 2023-12-22 18:31:20 -05:00 • committed by Andreas Kling
parent 4bd11c8eb4
commit 3ad9782e25
1 changed files with 19 additions and 15 deletions
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34
Userland/Libraries/LibPDF/Renderer.cpp
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@ -1170,6 +1170,24 @@ void Renderer::show_empty_image(int width, int height)
m_painter.stroke_path(rect_path(image_border), Color::Black, 1);
}
static ErrorOr<void> apply_alpha_channel(NonnullRefPtr<Gfx::Bitmap> image_bitmap, NonnullRefPtr<const Gfx::Bitmap> mask_bitmap)
{
// Make alpha mask same size as image.
if (mask_bitmap->size() != image_bitmap->size())
mask_bitmap = TRY(mask_bitmap->scaled_to_size(image_bitmap->size()));
image_bitmap->add_alpha_channel();
for (int j = 0; j < image_bitmap->height(); ++j) {
for (int i = 0; i < image_bitmap->width(); ++i) {
auto image_color = image_bitmap->get_pixel(i, j);
auto mask_color = mask_bitmap->get_pixel(i, j);
image_color = image_color.with_alpha(mask_color.luminosity());
image_bitmap->set_pixel(i, j, image_color);
}
}
return {};
}
PDFErrorOr<void> Renderer::show_image(NonnullRefPtr<StreamObject> image)
{
auto image_dict = image->dict();
@ -1183,21 +1201,7 @@ PDFErrorOr<void> Renderer::show_image(NonnullRefPtr<StreamObject> image)
auto image_bitmap = TRY(load_image(image));
if (image_dict->contains(CommonNames::SMask)) {
auto smask_bitmap = TRY(load_image(TRY(image_dict->get_stream(m_document, CommonNames::SMask))));
// Make softmask same size as image.
// FIXME: The smask code here is fairly ad-hoc and incomplete.
if (smask_bitmap->size() != image_bitmap->size())
smask_bitmap = TRY(smask_bitmap->scaled_to_size(image_bitmap->size()));
image_bitmap->add_alpha_channel();
for (int j = 0; j < image_bitmap->height(); ++j) {
for (int i = 0; i < image_bitmap->width(); ++i) {
auto image_color = image_bitmap->get_pixel(i, j);
auto smask_color = smask_bitmap->get_pixel(i, j);
image_color = image_color.with_alpha(smask_color.luminosity());
image_bitmap->set_pixel(i, j, image_color);
}
}
TRY(apply_alpha_channel(image_bitmap, smask_bitmap));
} else if (image_dict->contains(CommonNames::Mask)) {
auto mask_object = TRY(image_dict->get_object(m_document, CommonNames::Mask));
if (mask_object->is<StreamObject>()) {