ElyOffice/crates/ely-pdf-engine/shim/ely_output.c

/* Page images, text, optimized copies, repaired copies (PDF-13, PDF-14). */

#include <string.h>

#include "ely_shim.h"

/* Page `number` as a PNG at `dpi`, white, as printed. */
int ely_export_image(fz_context *ctx, fz_document *doc, int number, float dpi, const char *path)
{
	fz_pixmap *pixmap = NULL;
	fz_var(pixmap);
	fz_try(ctx)
	{
		if (dpi < 18 || dpi > 1200)
			fz_throw(ctx, FZ_ERROR_ARGUMENT, "a resolution outside 18 to 1200 dpi");
		ely_watch_begin(ctx);
		pixmap = fz_new_pixmap_from_page_number(ctx, doc, number, fz_scale(dpi / 72, dpi / 72), fz_device_rgb(ctx), 0);
		if (ely_watch_end(ctx))
			fz_throw(ctx, FZ_ERROR_FORMAT, "page %d did not read whole: %s", number + 1, ely_open_warnings());
		fz_save_pixmap_as_png(ctx, pixmap, path);
	}
	fz_always(ctx)
	{
		ely_watch_end(ctx);
		fz_drop_pixmap(ctx, pixmap);
	}
	fz_catch(ctx)
		return ely_fail(ctx);
	return 0;
}

/* Every page's text, UTF-8, pages parted by form feeds. */
int ely_export_text(fz_context *ctx, fz_document *doc, const char *path)
{
	fz_output *out = NULL;
	fz_stext_page *text = NULL;
	fz_buffer *buf = NULL;
	fz_var(out);
	fz_var(text);
	fz_var(buf);
	fz_try(ctx)
	{
		int i;
		ely_watch_begin(ctx);
		out = fz_new_output_with_path(ctx, path, 0);
		for (i = 0; i < fz_count_pages(ctx, doc); i++)
		{
			if (i > 0)
				fz_write_byte(ctx, out, '\f');
			text = fz_new_stext_page_from_page_number(ctx, doc, i, NULL);
			buf = fz_new_buffer_from_stext_page(ctx, text);
			fz_write_buffer(ctx, out, buf);
			fz_drop_buffer(ctx, buf);
			buf = NULL;
			fz_drop_stext_page(ctx, text);
			text = NULL;
		}
		/* Partial text is no export. */
		if (ely_watch_end(ctx))
			fz_throw(ctx, FZ_ERROR_FORMAT, "the text did not read whole: %s", ely_open_warnings());
		fz_close_output(ctx, out);
	}
	fz_always(ctx)
	{
		ely_watch_end(ctx);
		fz_drop_buffer(ctx, buf);
		fz_drop_stext_page(ctx, text);
		fz_drop_output(ctx, out);
	}
	fz_catch(ctx)
		return ely_fail(ctx);
	return 0;
}

typedef struct
{
	int from, to;
} downsample;

static void shrink_images(fz_context *ctx, fz_document *copy, void *arg)
{
	downsample *d = arg;
	pdf_image_rewriter_options opts = { 0 };
	if (!d->to)
		return;
	opts.color_lossless_image_subsample_method = opts.color_lossy_image_subsample_method = FZ_SUBSAMPLE_BICUBIC;
	opts.gray_lossless_image_subsample_method = opts.gray_lossy_image_subsample_method = FZ_SUBSAMPLE_BICUBIC;
	opts.bitonal_image_subsample_method = FZ_SUBSAMPLE_BICUBIC;
	opts.color_lossless_image_subsample_threshold = opts.color_lossy_image_subsample_threshold = d->from;
	opts.gray_lossless_image_subsample_threshold = opts.gray_lossy_image_subsample_threshold = d->from;
	opts.bitonal_image_subsample_threshold = d->from;
	opts.color_lossless_image_subsample_to = opts.color_lossy_image_subsample_to = d->to;
	opts.gray_lossless_image_subsample_to = opts.gray_lossy_image_subsample_to = d->to;
	opts.bitonal_image_subsample_to = d->to;
	/* Never, the default, drops the smaller picture. */
	opts.color_lossless_image_recompress_method = opts.gray_lossless_image_recompress_method = FZ_RECOMPRESS_LOSSLESS;
	opts.color_lossy_image_recompress_method = opts.gray_lossy_image_recompress_method = FZ_RECOMPRESS_SAME;
	opts.bitonal_image_recompress_method = FZ_RECOMPRESS_SAME;
	pdf_rewrite_images(ctx, ely_pdf_of(ctx, copy), &opts);
}

/* Writes `out` compressed, images above `from` dpi taken to `to`. */
int ely_optimize(fz_context *ctx, fz_document *doc, const char *raw, const char *out, const char *password, int compress,
	int from, int to)
{
	fz_try(ctx)
	{
		pdf_write_options opts = pdf_default_write_options;
		downsample d = { from, to };
		if (to && (to < 36 || from <= to))
			fz_throw(ctx, FZ_ERROR_ARGUMENT, "a downsampling from %d to %d dpi", from, to);
		opts.do_compress = opts.do_compress_images = opts.do_compress_fonts = compress;
		ely_save_copy(ctx, ely_pdf_of(ctx, doc), raw, out, password, &opts, shrink_images, &d);
	}
	fz_catch(ctx)
		return ely_fail(ctx);
	return 0;
}

/* 1 when MuPDF rebuilt the file's structure to read it. */
int ely_repaired(fz_context *ctx, fz_document *doc)
{
	int repaired = 0;
	fz_try(ctx)
		repaired = pdf_was_repaired(ctx, ely_pdf_of(ctx, doc));
	fz_catch(ctx)
		return ely_fail(ctx);
	return repaired;
}

/* The repaired document written whole to `path`. */
int ely_write_repaired(fz_context *ctx, fz_document *doc, const char *path)
{
	fz_try(ctx)
	{
		pdf_write_options opts = pdf_default_write_options;
		opts.do_garbage = 1;
		pdf_save_document(ctx, ely_pdf_of(ctx, doc), path, &opts);
	}
	fz_catch(ctx)
		return ely_fail(ctx);
	return 0;
}

/* Leave to print was checked; the printer gets no lock. */
int ely_print_copy(fz_context *ctx, fz_document *doc, const char *raw, const char *out, const char *password)
{
	fz_try(ctx)
	{
		pdf_write_options opts = pdf_default_write_options;
		opts.do_encrypt = PDF_ENCRYPT_NONE;
		ely_save_copy(ctx, ely_pdf_of(ctx, doc), raw, out, password, &opts, NULL, NULL);
	}
	fz_catch(ctx)
		return ely_fail(ctx);
	return 0;
}

/* Decodes every picture; 1 if MuPDF warned on any. */
int ely_check_pictures(fz_context *ctx, fz_document *doc)
{
	pdf_document *pdf = ely_pdf_of(ctx, doc);
	int i;
	ely_watch_begin(ctx);
	for (i = 1; i < pdf_xref_len(ctx, pdf); i++)
	{
		pdf_obj *obj = NULL;
		fz_buffer *bytes = NULL;
		fz_var(obj);
		fz_var(bytes);
		fz_try(ctx)
		{
			obj = pdf_new_indirect(ctx, pdf, i, 0);
			if (pdf_is_stream(ctx, obj) && pdf_name_eq(ctx, pdf_dict_get(ctx, obj, PDF_NAME(Subtype)), PDF_NAME(Image)))
				bytes = pdf_load_stream_number(ctx, pdf, i);
		}
		fz_always(ctx)
		{
			fz_drop_buffer(ctx, bytes);
			pdf_drop_obj(ctx, obj);
		}
		fz_catch(ctx)
		{
			fz_warn(ctx, "picture %d: %s", i, fz_caught_message(ctx));
			fz_ignore_error(ctx);
		}
	}
	return ely_watch_end(ctx);
}