godot/modules/jpg/image_loader_libjpeg_turbo.cpp

/**************************************************************************/
/*  image_loader_libjpeg_turbo.cpp                                        */
/**************************************************************************/
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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#include "image_loader_libjpeg_turbo.h"

#include <turbojpeg.h>

Error jpeg_turbo_load_image_from_buffer(Image *p_image, const uint8_t *p_buffer, int p_buffer_len) {
	tjhandle tj_instance = tj3Init(TJINIT_DECOMPRESS);
	if (tj_instance == NULL) {
		return FAILED;
	}

	if (tj3DecompressHeader(tj_instance, p_buffer, p_buffer_len) < 0) {
		tj3Destroy(tj_instance);
		return ERR_FILE_CORRUPT;
	}

	const unsigned int width = tj3Get(tj_instance, TJPARAM_JPEGWIDTH);
	const unsigned int height = tj3Get(tj_instance, TJPARAM_JPEGHEIGHT);
	const TJCS colorspace = (TJCS)tj3Get(tj_instance, TJPARAM_COLORSPACE);

	if (tj3Get(tj_instance, TJPARAM_PRECISION) > 8) {
		// Proceed anyway and convert to rgb8?
		tj3Destroy(tj_instance);
		return ERR_UNAVAILABLE;
	}

	TJPF tj_pixel_format;
	Image::Format gd_pixel_format;
	if (colorspace == TJCS_GRAY) {
		tj_pixel_format = TJPF_GRAY;
		gd_pixel_format = Image::FORMAT_L8;
	} else {
		// Force everything else (RGB, CMYK etc) into RGB8.
		tj_pixel_format = TJPF_RGB;
		gd_pixel_format = Image::FORMAT_RGB8;
	}

	Vector<uint8_t> data;
	data.resize(width * height * tjPixelSize[tj_pixel_format]);

	if (tj3Decompress8(tj_instance, p_buffer, p_buffer_len, data.ptrw(), 0, tj_pixel_format) < 0) {
		tj3Destroy(tj_instance);
		return ERR_FILE_CORRUPT;
	}

	tj3Destroy(tj_instance);
	p_image->set_data(width, height, false, gd_pixel_format, data);
	return OK;
}

Error ImageLoaderLibJPEGTurbo::load_image(Ref<Image> p_image, Ref<FileAccess> f, BitField<ImageFormatLoader::LoaderFlags> p_flags, float p_scale) {
	Vector<uint8_t> src_image;
	uint64_t src_image_len = f->get_length();
	ERR_FAIL_COND_V(src_image_len == 0, ERR_FILE_CORRUPT);
	src_image.resize(src_image_len);

	uint8_t *w = src_image.ptrw();

	f->get_buffer(&w[0], src_image_len);

	Error err = jpeg_turbo_load_image_from_buffer(p_image.ptr(), w, src_image_len);

	return err;
}

void ImageLoaderLibJPEGTurbo::get_recognized_extensions(List<String> *p_extensions) const {
	p_extensions->push_back("jpg");
	p_extensions->push_back("jpeg");
}

static Ref<Image> _jpeg_turbo_mem_loader_func(const uint8_t *p_png, int p_size) {
	Ref<Image> img;
	img.instantiate();
	Error err = jpeg_turbo_load_image_from_buffer(img.ptr(), p_png, p_size);
	ERR_FAIL_COND_V(err, Ref<Image>());
	return img;
}

static Vector<uint8_t> _jpeg_turbo_buffer_save_func(const Ref<Image> &p_img, float p_quality) {
	Vector<uint8_t> output;

	ERR_FAIL_COND_V(p_img.is_null() || p_img->is_empty(), output);

	Ref<Image> image = p_img->duplicate();
	if (image->is_compressed()) {
		Error error = image->decompress();
		ERR_FAIL_COND_V_MSG(error != OK, output, "Couldn't decompress image.");
	}

	if (image->get_format() != Image::FORMAT_RGB8) {
		// Allow grayscale L8?
		image = image->duplicate();
		image->convert(Image::FORMAT_RGB8);
	}

	tjhandle tj_instance = tj3Init(TJINIT_COMPRESS);
	ERR_FAIL_COND_V_MSG(tj_instance == NULL, output, "Couldn't create tjhandle");

	if (tj3Set(tj_instance, TJPARAM_QUALITY, (int)(p_quality * 100)) < 0) {
		tj3Destroy(tj_instance);
		ERR_FAIL_V_MSG(output, "Couldn't set jpg quality");
	}

	if (tj3Set(tj_instance, TJPARAM_PRECISION, 8) < 0) {
		tj3Destroy(tj_instance);
		ERR_FAIL_V_MSG(output, "Couldn't set jpg precision");
	}

	if (tj3Set(tj_instance, TJPARAM_SUBSAMP, TJSAMP_420) < 0) {
		tj3Destroy(tj_instance);
		ERR_FAIL_V_MSG(output, "Couldn't set jpg subsamples");
	}

	// If the godot image format is `Image::FORMAT_L8` we could set the appropriate
	// color space here rather than defaulting to RGB.

	unsigned char *jpeg_buff = NULL;
	size_t jpeg_size = 0;
	int code = tj3Compress8(
			tj_instance,
			image->get_data().ptr(),
			image->get_width(),
			0,
			image->get_height(),
			TJPF_RGB,
			&jpeg_buff,
			&jpeg_size);

	if (code < 0) {
		tj3Destroy(tj_instance);
		tj3Free(jpeg_buff);
		ERR_FAIL_V_MSG(output, "Couldn't compress jpg");
	}

	output.resize(jpeg_size);
	memcpy(output.ptrw(), jpeg_buff, jpeg_size);

	tj3Destroy(tj_instance);
	tj3Free(jpeg_buff);

	return output;
}

static Error _jpeg_turbo_save_func(const String &p_path, const Ref<Image> &p_img, float p_quality) {
	Error err;
	Ref<FileAccess> file = FileAccess::open(p_path, FileAccess::WRITE, &err);
	ERR_FAIL_COND_V_MSG(err, err, vformat("Can't save JPG at path: '%s'.", p_path));

	Vector<uint8_t> data = _jpeg_turbo_buffer_save_func(p_img, p_quality);
	ERR_FAIL_COND_V(data.size() == 0, FAILED);
	ERR_FAIL_COND_V_MSG(!file->store_buffer(data.ptr(), data.size()), FAILED, "Failed writing jpg to file");

	return OK;
}

ImageLoaderLibJPEGTurbo::ImageLoaderLibJPEGTurbo() {
	Image::_jpg_mem_loader_func = _jpeg_turbo_mem_loader_func;
	Image::save_jpg_func = _jpeg_turbo_save_func;
	Image::save_jpg_buffer_func = _jpeg_turbo_buffer_save_func;
}