eBookReaderSwitch/mupdf/source/pdf/pdf-image.c

#include "mupdf/fitz.h"
#include "mupdf/pdf.h"

#include <string.h>

static fz_image *pdf_load_jpx(fz_context *ctx, pdf_document *doc, pdf_obj *dict, int forcemask);

static fz_image *
pdf_load_jpx_imp(fz_context *ctx, pdf_document *doc, pdf_obj *rdb, pdf_obj *dict, fz_stream *cstm, int forcemask)
{
	fz_image *image = pdf_load_jpx(ctx, doc, dict, forcemask);

	if (forcemask)
	{
		fz_pixmap_image *cimg = (fz_pixmap_image *)image;
		fz_pixmap *mask_pixmap;
		fz_pixmap *tile = fz_pixmap_image_tile(ctx, cimg);

		if (tile->n != 1)
		{
			fz_pixmap *gray = fz_convert_pixmap(ctx, tile, fz_device_gray(ctx), NULL, NULL, fz_default_color_params, 0);
			fz_drop_pixmap(ctx, tile);
			tile = gray;
		}

		mask_pixmap = fz_alpha_from_gray(ctx, tile);
		fz_drop_pixmap(ctx, tile);
		fz_set_pixmap_image_tile(ctx, cimg, mask_pixmap);
	}

	return image;
}

static fz_image *
pdf_load_image_imp(fz_context *ctx, pdf_document *doc, pdf_obj *rdb, pdf_obj *dict, fz_stream *cstm, int forcemask)
{
	fz_image *image = NULL;
	pdf_obj *obj, *res;

	int w, h, bpc, n;
	int imagemask;
	int interpolate;
	int indexed;
	fz_image *mask = NULL; /* explicit mask/soft mask image */
	int use_colorkey = 0;
	fz_colorspace *colorspace = NULL;
	float decode[FZ_MAX_COLORS * 2];
	int colorkey[FZ_MAX_COLORS * 2];
	int stride;

	int i;
	fz_compressed_buffer *buffer;

	/* special case for JPEG2000 images */
	if (pdf_is_jpx_image(ctx, dict))
		return pdf_load_jpx_imp(ctx, doc, rdb, dict, cstm, forcemask);

	w = pdf_to_int(ctx, pdf_dict_geta(ctx, dict, PDF_NAME(Width), PDF_NAME(W)));
	h = pdf_to_int(ctx, pdf_dict_geta(ctx, dict, PDF_NAME(Height), PDF_NAME(H)));
	bpc = pdf_to_int(ctx, pdf_dict_geta(ctx, dict, PDF_NAME(BitsPerComponent), PDF_NAME(BPC)));
	if (bpc == 0)
		bpc = 8;
	imagemask = pdf_to_bool(ctx, pdf_dict_geta(ctx, dict, PDF_NAME(ImageMask), PDF_NAME(IM)));
	interpolate = pdf_to_bool(ctx, pdf_dict_geta(ctx, dict, PDF_NAME(Interpolate), PDF_NAME(I)));

	indexed = 0;
	use_colorkey = 0;

	if (imagemask)
		bpc = 1;

	if (w <= 0)
		fz_throw(ctx, FZ_ERROR_GENERIC, "image width is zero (or less)");
	if (h <= 0)
		fz_throw(ctx, FZ_ERROR_GENERIC, "image height is zero (or less)");
	if (bpc <= 0)
		fz_throw(ctx, FZ_ERROR_GENERIC, "image depth is zero (or less)");
	if (bpc > 16)
		fz_throw(ctx, FZ_ERROR_GENERIC, "image depth is too large: %d", bpc);
	if (w > (1 << 16))
		fz_throw(ctx, FZ_ERROR_GENERIC, "image is too wide");
	if (h > (1 << 16))
		fz_throw(ctx, FZ_ERROR_GENERIC, "image is too high");

	fz_var(mask);
	fz_var(image);
	fz_var(colorspace);

	fz_try(ctx)
	{
		obj = pdf_dict_geta(ctx, dict, PDF_NAME(ColorSpace), PDF_NAME(CS));
		if (obj && !imagemask && !forcemask)
		{
			/* colorspace resource lookup is only done for inline images */
			if (pdf_is_name(ctx, obj))
			{
				res = pdf_dict_get(ctx, pdf_dict_get(ctx, rdb, PDF_NAME(ColorSpace)), obj);
				if (res)
					obj = res;
			}

			colorspace = pdf_load_colorspace(ctx, obj);
			indexed = fz_colorspace_is_indexed(ctx, colorspace);

			n = fz_colorspace_n(ctx, colorspace);
		}
		else
		{
			n = 1;
		}

		obj = pdf_dict_geta(ctx, dict, PDF_NAME(Decode), PDF_NAME(D));
		if (obj)
		{
			for (i = 0; i < n * 2; i++)
				decode[i] = pdf_array_get_real(ctx, obj, i);
		}
		else if (fz_colorspace_is_lab(ctx, colorspace))
		{
			decode[0] = 0;
			decode[1] = 100;
			decode[2] = -128;
			decode[3] = 127;
			decode[4] = -128;
			decode[5] = 127;
		}
		else
		{
			float maxval = indexed ? (1 << bpc) - 1 : 1;
			for (i = 0; i < n * 2; i++)
				decode[i] = i & 1 ? maxval : 0;
		}

		obj = pdf_dict_geta(ctx, dict, PDF_NAME(SMask), PDF_NAME(Mask));
		if (pdf_is_dict(ctx, obj))
		{
			/* Not allowed for inline images or soft masks */
			if (cstm)
				fz_warn(ctx, "Ignoring invalid inline image soft mask");
			else if (forcemask)
				fz_warn(ctx, "Ignoring recursive image soft mask");
			else
			{
				mask = pdf_load_image_imp(ctx, doc, rdb, obj, NULL, 1);
				obj = pdf_dict_get(ctx, obj, PDF_NAME(Matte));
				if (pdf_is_array(ctx, obj))
				{
					use_colorkey = 1;
					for (i = 0; i < n; i++)
						colorkey[i] = pdf_array_get_real(ctx, obj, i) * 255;
				}
			}
		}
		else if (pdf_is_array(ctx, obj))
		{
			use_colorkey = 1;
			for (i = 0; i < n * 2; i++)
			{
				if (!pdf_is_int(ctx, pdf_array_get(ctx, obj, i)))
				{
					fz_warn(ctx, "invalid value in color key mask");
					use_colorkey = 0;
				}
				colorkey[i] = pdf_array_get_int(ctx, obj, i);
			}
		}

		/* Do we load from a ref, or do we load an inline stream? */
		if (cstm == NULL)
		{
			/* Just load the compressed image data now and we can decode it on demand. */
			buffer = pdf_load_compressed_stream(ctx, doc, pdf_to_num(ctx, dict));
			image = fz_new_image_from_compressed_buffer(ctx, w, h, bpc, colorspace, 96, 96, interpolate, imagemask, decode, use_colorkey ? colorkey : NULL, buffer, mask);
			image->invert_cmyk_jpeg = 0;
		}
		else
		{
			/* Inline stream */
			stride = (w * n * bpc + 7) / 8;
			image = fz_new_image_from_compressed_buffer(ctx, w, h, bpc, colorspace, 96, 96, interpolate, imagemask, decode, use_colorkey ? colorkey : NULL, NULL, mask);
			image->invert_cmyk_jpeg = 0;
			pdf_load_compressed_inline_image(ctx, doc, dict, stride * h, cstm, indexed, (fz_compressed_image *)image);
		}
	}
	fz_always(ctx)
	{
		fz_drop_colorspace(ctx, colorspace);
		fz_drop_image(ctx, mask);
	}
	fz_catch(ctx)
	{
		fz_drop_image(ctx, image);
		fz_rethrow(ctx);
	}
	return image;
}

fz_image *
pdf_load_inline_image(fz_context *ctx, pdf_document *doc, pdf_obj *rdb, pdf_obj *dict, fz_stream *file)
{
	return pdf_load_image_imp(ctx, doc, rdb, dict, file, 0);
}

int
pdf_is_jpx_image(fz_context *ctx, pdf_obj *dict)
{
	pdf_obj *filter;
	int i, n;

	filter = pdf_dict_get(ctx, dict, PDF_NAME(Filter));
	if (pdf_name_eq(ctx, filter, PDF_NAME(JPXDecode)))
		return 1;
	n = pdf_array_len(ctx, filter);
	for (i = 0; i < n; i++)
		if (pdf_name_eq(ctx, pdf_array_get(ctx, filter, i), PDF_NAME(JPXDecode)))
			return 1;
	return 0;
}

static fz_image *
pdf_load_jpx(fz_context *ctx, pdf_document *doc, pdf_obj *dict, int forcemask)
{
	fz_buffer *buf = NULL;
	fz_colorspace *colorspace = NULL;
	fz_pixmap *pix = NULL;
	pdf_obj *obj;
	fz_image *mask = NULL;
	fz_image *img = NULL;

	fz_var(pix);
	fz_var(buf);
	fz_var(colorspace);
	fz_var(mask);

	buf = pdf_load_stream(ctx, dict);

	/* FIXME: We can't handle decode arrays for indexed images currently */
	fz_try(ctx)
	{
		unsigned char *data;
		size_t len;

		obj = pdf_dict_get(ctx, dict, PDF_NAME(ColorSpace));
		if (obj)
			colorspace = pdf_load_colorspace(ctx, obj);

		len = fz_buffer_storage(ctx, buf, &data);
		pix = fz_load_jpx(ctx, data, len, colorspace);

		obj = pdf_dict_geta(ctx, dict, PDF_NAME(SMask), PDF_NAME(Mask));
		if (pdf_is_dict(ctx, obj))
		{
			if (forcemask)
				fz_warn(ctx, "Ignoring recursive JPX soft mask");
			else
				mask = pdf_load_image_imp(ctx, doc, NULL, obj, NULL, 1);
		}

		obj = pdf_dict_geta(ctx, dict, PDF_NAME(Decode), PDF_NAME(D));
		if (obj && !fz_colorspace_is_indexed(ctx, colorspace))
		{
			float decode[FZ_MAX_COLORS * 2];
			int i;

			for (i = 0; i < pix->n * 2; i++)
				decode[i] = pdf_array_get_real(ctx, obj, i);

			fz_decode_tile(ctx, pix, decode);
		}

		img = fz_new_image_from_pixmap(ctx, pix, mask);
	}
	fz_always(ctx)
	{
		fz_drop_image(ctx, mask);
		fz_drop_pixmap(ctx, pix);
		fz_drop_colorspace(ctx, colorspace);
		fz_drop_buffer(ctx, buf);
	}
	fz_catch(ctx)
	{
		fz_rethrow(ctx);
	}

	return img;
}

fz_image *
pdf_load_image(fz_context *ctx, pdf_document *doc, pdf_obj *dict)
{
	fz_image *image;

	if ((image = pdf_find_item(ctx, fz_drop_image_imp, dict)) != NULL)
		return image;

	image = pdf_load_image_imp(ctx, doc, NULL, dict, NULL, 0);
	pdf_store_item(ctx, dict, image, fz_image_size(ctx, image));
	return image;
}

pdf_obj *
pdf_add_image(fz_context *ctx, pdf_document *doc, fz_image *image)
{
	fz_pixmap *pixmap = NULL;
	pdf_obj *imobj = NULL;
	pdf_obj *dp;
	fz_buffer *buffer = NULL;
	pdf_obj *imref = NULL;
	fz_compressed_buffer *cbuffer;
	unsigned char digest[16];
	int i, n;

	/* If we can maintain compression, do so */
	cbuffer = fz_compressed_image_buffer(ctx, image);

	fz_var(pixmap);
	fz_var(buffer);
	fz_var(imobj);
	fz_var(imref);

	/* Check if the same image already exists in this doc. */
	imref = pdf_find_image_resource(ctx, doc, image, digest);
	if (imref)
		return imref;

	imobj = pdf_add_new_dict(ctx, doc, 3);
	fz_try(ctx)
	{
		dp = pdf_dict_put_dict(ctx, imobj, PDF_NAME(DecodeParms), 3);
		pdf_dict_put(ctx, imobj, PDF_NAME(Type), PDF_NAME(XObject));
		pdf_dict_put(ctx, imobj, PDF_NAME(Subtype), PDF_NAME(Image));

		if (cbuffer)
		{
			fz_compression_params *cp = &cbuffer->params;
			switch (cp ? cp->type : FZ_IMAGE_UNKNOWN)
			{
			default:
				goto raw_or_unknown_compression;
			case FZ_IMAGE_JPEG:
				if (cp->u.jpeg.color_transform != -1)
					pdf_dict_put_int(ctx, dp, PDF_NAME(ColorTransform), cp->u.jpeg.color_transform);
				pdf_dict_put(ctx, imobj, PDF_NAME(Filter), PDF_NAME(DCTDecode));
				break;
			case FZ_IMAGE_JPX:
				if (cp->u.jpx.smask_in_data)
					pdf_dict_put_int(ctx, dp, PDF_NAME(SMaskInData), cp->u.jpx.smask_in_data);
				pdf_dict_put(ctx, imobj, PDF_NAME(Filter), PDF_NAME(JPXDecode));
				break;
			case FZ_IMAGE_FAX:
				if (cp->u.fax.columns)
					pdf_dict_put_int(ctx, dp, PDF_NAME(Columns), cp->u.fax.columns);
				if (cp->u.fax.rows)
					pdf_dict_put_int(ctx, dp, PDF_NAME(Rows), cp->u.fax.rows);
				if (cp->u.fax.k)
					pdf_dict_put_int(ctx, dp, PDF_NAME(K), cp->u.fax.k);
				if (cp->u.fax.end_of_line)
					pdf_dict_put_bool(ctx, dp, PDF_NAME(EndOfLine), cp->u.fax.end_of_line);
				if (cp->u.fax.encoded_byte_align)
					pdf_dict_put_bool(ctx, dp, PDF_NAME(EncodedByteAlign), cp->u.fax.encoded_byte_align);
				if (cp->u.fax.end_of_block)
					pdf_dict_put_bool(ctx, dp, PDF_NAME(EndOfBlock), cp->u.fax.end_of_block);
				if (cp->u.fax.black_is_1)
					pdf_dict_put_bool(ctx, dp, PDF_NAME(BlackIs1), cp->u.fax.black_is_1);
				if (cp->u.fax.damaged_rows_before_error)
					pdf_dict_put_int(ctx, dp, PDF_NAME(DamagedRowsBeforeError), cp->u.fax.damaged_rows_before_error);
				pdf_dict_put(ctx, imobj, PDF_NAME(Filter), PDF_NAME(CCITTFaxDecode));
				break;
			case FZ_IMAGE_FLATE:
				if (cp->u.flate.columns)
					pdf_dict_put_int(ctx, dp, PDF_NAME(Columns), cp->u.flate.columns);
				if (cp->u.flate.colors)
					pdf_dict_put_int(ctx, dp, PDF_NAME(Colors), cp->u.flate.colors);
				if (cp->u.flate.predictor)
					pdf_dict_put_int(ctx, dp, PDF_NAME(Predictor), cp->u.flate.predictor);
				if (cp->u.flate.bpc)
					pdf_dict_put_int(ctx, dp, PDF_NAME(BitsPerComponent), cp->u.flate.bpc);
				pdf_dict_put(ctx, imobj, PDF_NAME(Filter), PDF_NAME(FlateDecode));
				pdf_dict_put_int(ctx, imobj, PDF_NAME(BitsPerComponent), image->bpc);
				break;
			case FZ_IMAGE_LZW:
				if (cp->u.lzw.columns)
					pdf_dict_put_int(ctx, dp, PDF_NAME(Columns), cp->u.lzw.columns);
				if (cp->u.lzw.colors)
					pdf_dict_put_int(ctx, dp, PDF_NAME(Colors), cp->u.lzw.colors);
				if (cp->u.lzw.predictor)
					pdf_dict_put_int(ctx, dp, PDF_NAME(Predictor), cp->u.lzw.predictor);
				if (cp->u.lzw.early_change)
					pdf_dict_put_int(ctx, dp, PDF_NAME(EarlyChange), cp->u.lzw.early_change);
				if (cp->u.lzw.bpc)
					pdf_dict_put_int(ctx, dp, PDF_NAME(BitsPerComponent), cp->u.lzw.bpc);
				pdf_dict_put(ctx, imobj, PDF_NAME(Filter), PDF_NAME(LZWDecode));
				break;
			case FZ_IMAGE_RLD:
				pdf_dict_put(ctx, imobj, PDF_NAME(Filter), PDF_NAME(RunLengthDecode));
				break;
			}

			if (!pdf_dict_len(ctx, dp))
				pdf_dict_del(ctx, imobj, PDF_NAME(DecodeParms));

			buffer = fz_keep_buffer(ctx, cbuffer->buffer);

			if (image->use_decode)
			{
				pdf_obj *ary = pdf_dict_put_array(ctx, imobj, PDF_NAME(Decode), image->n * 2);
				for (i = 0; i < image->n * 2; ++i)
					pdf_array_push_real(ctx, ary, image->decode[i]);
			}
		}
		else
		{
			unsigned int size;
			int h;
			unsigned char *d, *s;

raw_or_unknown_compression:
			/* Currently, set to maintain resolution; should we consider
			 * subsampling here according to desired output res? */
			pixmap = fz_get_pixmap_from_image(ctx, image, NULL, NULL, NULL, NULL);
			n = pixmap->n - pixmap->alpha - pixmap->s; /* number of colorants */
			if (n == 0)
				n = 1; /* treat pixmaps with only alpha or spots as grayscale */

			size = image->w * n;
			h = image->h;
			s = pixmap->samples;
			d = fz_malloc(ctx, size * h);
			buffer = fz_new_buffer_from_data(ctx, d, size * h);

			if (n == pixmap->n)
			{
				/* If we use all channels, we can copy the data as is. */
				while (h--)
				{
					memcpy(d, s, size);
					d += size;
					s += pixmap->stride;
				}
			}
			else
			{
				/* Need to remove the alpha and spot planes. */
				/* TODO: extract alpha plane to a soft mask. */
				/* TODO: convert spots to colors. */

				int line_skip = pixmap->stride - pixmap->w * pixmap->n;
				int skip = pixmap->n - n;
				while (h--)
				{
					int w = pixmap->w;
					while (w--)
					{
						int k;
						for (k = 0; k < n; ++k)
							*d++ = *s++;
						s += skip;
					}
					s += line_skip;
				}
			}
		}

		pdf_dict_put_int(ctx, imobj, PDF_NAME(Width), pixmap ? pixmap->w : image->w);
		pdf_dict_put_int(ctx, imobj, PDF_NAME(Height), pixmap ? pixmap->h : image->h);

		if (image->imagemask)
		{
			pdf_dict_put_bool(ctx, imobj, PDF_NAME(ImageMask), 1);
		}
		else
		{
			fz_colorspace *cs;

			pdf_dict_put_int(ctx, imobj, PDF_NAME(BitsPerComponent), image->bpc);

			cs = pixmap ? pixmap->colorspace : image->colorspace;
			switch (fz_colorspace_type(ctx, cs))
			{
			case FZ_COLORSPACE_INDEXED:
				{
					fz_colorspace *basecs;
					unsigned char *lookup = NULL;
					int high = 0;
					int basen;
					pdf_obj *arr;

					basecs = cs->u.indexed.base;
					high = cs->u.indexed.high;
					lookup = cs->u.indexed.lookup;
					basen = basecs->n;

					arr = pdf_dict_put_array(ctx, imobj, PDF_NAME(ColorSpace), 4);

					pdf_array_push(ctx, arr, PDF_NAME(Indexed));
					switch (fz_colorspace_type(ctx, basecs))
					{
					case FZ_COLORSPACE_GRAY:
						pdf_array_push(ctx, arr, PDF_NAME(DeviceGray));
						break;
					case FZ_COLORSPACE_RGB:
						pdf_array_push(ctx, arr, PDF_NAME(DeviceRGB));
						break;
					case FZ_COLORSPACE_CMYK:
						pdf_array_push(ctx, arr, PDF_NAME(DeviceCMYK));
						break;
					default:
						// TODO: convert to RGB!
						fz_throw(ctx, FZ_ERROR_GENERIC, "only indexed Gray, RGB, and CMYK colorspaces supported");
						break;
					}

					pdf_array_push_int(ctx, arr, high);
					pdf_array_push_string(ctx, arr, (char *) lookup, basen * (high + 1));
				}
				break;
			case FZ_COLORSPACE_NONE:
			case FZ_COLORSPACE_GRAY:
				pdf_dict_put(ctx, imobj, PDF_NAME(ColorSpace), PDF_NAME(DeviceGray));
				break;
			case FZ_COLORSPACE_RGB:
				pdf_dict_put(ctx, imobj, PDF_NAME(ColorSpace), PDF_NAME(DeviceRGB));
				break;
			case FZ_COLORSPACE_CMYK:
				pdf_dict_put(ctx, imobj, PDF_NAME(ColorSpace), PDF_NAME(DeviceCMYK));
				break;
			default:
				// TODO: convert to RGB!
				fz_throw(ctx, FZ_ERROR_GENERIC, "only Gray, RGB, and CMYK colorspaces supported");
				break;
			}
		}

		if (image->mask)
		{
			pdf_dict_put_drop(ctx, imobj, PDF_NAME(SMask), pdf_add_image(ctx, doc, image->mask));
		}

		pdf_update_stream(ctx, doc, imobj, buffer, 1);

		/* Add ref to our image resource hash table. */
		imref = pdf_insert_image_resource(ctx, doc, digest, imobj);
	}
	fz_always(ctx)
	{
		fz_drop_pixmap(ctx, pixmap);
		fz_drop_buffer(ctx, buffer);
		pdf_drop_obj(ctx, imobj);
	}
	fz_catch(ctx)
		fz_rethrow(ctx);
	return imref;
}