pdf_build.c

SumatraPDF是一款小型开源的pdf阅读工具。虽然玲珑小巧（只有800多KB）

	{
	case PDF_MNONE:
		fz_insertnodelast(gs->head, shape);
		break;

	case PDF_MCOLOR:
	case PDF_MLAB:
	case PDF_MINDEXED:
		error = addcolorshape(gs, shape, gs->fill.alpha, gs->fill.cs, gs->fill.v);
		if (error)
			return fz_rethrow(error, "cannot add colored shape");
		break;

	case PDF_MPATTERN:
		error = addpatternshape(gs, shape, gs->fill.pattern, gs->fill.cs, gs->fill.v);
		if (error)
			return fz_rethrow(error, "cannot add pattern shape");
		break;

	case PDF_MSHADE:
		error = addshadeshape(gs, shape, gs->fill.shade);
		if (error)
			return fz_rethrow(error, "cannot add shade shape");
		break;

	default:
		return fz_throw("assert: unknown material");
	}

	return fz_okay;
}

fz_error *
pdf_addstrokeshape(pdf_gstate *gs, fz_node *shape)
{
	fz_error *error;

	switch (gs->stroke.kind)
	{
	case PDF_MNONE:
		fz_insertnodelast(gs->head, shape);
		break;

	case PDF_MCOLOR:
	case PDF_MLAB:
	case PDF_MINDEXED:
		error = addcolorshape(gs, shape, gs->stroke.alpha, gs->stroke.cs, gs->stroke.v);
		if (error)
			return fz_rethrow(error, "cannot add colored shape");
		break;

	case PDF_MPATTERN:
		error = addpatternshape(gs, shape, gs->stroke.pattern, gs->stroke.cs, gs->stroke.v);
		if (error)
			return fz_rethrow(error, "cannot add pattern shape");
		break;

	case PDF_MSHADE:
		error = addshadeshape(gs, shape, gs->stroke.shade);
		if (error)
			return fz_rethrow(error, "cannot add shade shape");
		break;

	default:
		return fz_throw("assert: unknown material");
	}

	return fz_okay;
}

fz_error *
pdf_addclipmask(pdf_gstate *gs, fz_node *shape)
{
	fz_error *error;
	fz_node *mask;
	fz_node *over;

	error = fz_newmasknode(&mask);
	if (error)
		return fz_rethrow(error, "cannot create mask node");

	error = pdf_newovernode(&over, gs);
	if (error)
	{
		fz_dropnode(mask);
		return fz_rethrow(error, "cannot create over node");
	}

	fz_insertnodelast(mask, shape);
	fz_insertnodelast(mask, over);
	fz_insertnodelast(gs->head, mask);
	gs->head = over;

	return fz_okay;
}

fz_error *
pdf_addtransform(pdf_gstate *gs, fz_node *transform)
{
	fz_error *error;
	fz_node *over;

	error = pdf_newovernode(&over, gs);
	if (error)
		return fz_rethrow(error, "cannot create over node");

	fz_insertnodelast(gs->head, transform);
	fz_insertnodelast(transform, over);
	gs->head = over;

	return fz_okay;
}

fz_error *
pdf_showimage(pdf_csi *csi, pdf_image *img)
{
	fz_error *error;
	fz_node *mask;
	fz_node *color;
	fz_node *shape;

	error = fz_newimagenode(&color, (fz_image*)img);
	if (error)
		return fz_rethrow(error, "cannot create image node");

	if (img->super.n == 0 && img->super.a == 1)
	{
		error = pdf_addfillshape(csi->gstate + csi->gtop, color);
		if (error)
		{
			fz_dropnode(color);
			return fz_rethrow(error, "cannot add filled image mask");
		}
	}

	else
	{
		if (img->mask)
		{
			error = fz_newimagenode(&shape, (fz_image*)img->mask);
			if (error)
			{
				fz_dropnode(color);
				return fz_rethrow(error, "cannot create image node for image mask");
			}
			error = fz_newmasknode(&mask);
			if (error)
			{
				fz_dropnode(shape);
				fz_dropnode(color);
				return fz_rethrow(error, "cannot create mask node for image mask");
			}
			fz_insertnodelast(mask, shape);
			fz_insertnodelast(mask, color);
			fz_insertnodelast(csi->gstate[csi->gtop].head, mask);
		}
		else
		{
			fz_insertnodelast(csi->gstate[csi->gtop].head, color);
		}
	}

	return fz_okay;
}

fz_error *
pdf_showpath(pdf_csi *csi,
		int doclose, int dofill, int dostroke, int evenodd)
{
	pdf_gstate *gstate = csi->gstate + csi->gtop;
	fz_error *error;
	char *reason;
	fz_pathnode *spath = nil;
	fz_pathnode *fpath = nil;
	fz_pathnode *clip = nil;

	/* TODO review memory cleanup code cleanup... */

	if (doclose)
	{
		error = fz_closepath(csi->path);
		if (error)
			return fz_rethrow(error, "cannot create path node");
	}

	/*
	 * Prepare the various copies of the path node.
	 */

	if (csi->clip)
	{
		error = fz_clonepathnode(&clip, csi->path);
		if (error)
			return fz_rethrow(error, "cannot copy path node for clip mask");
	}

	if (dofill && dostroke)
	{
		fpath = csi->path;
		error = fz_clonepathnode(&spath, fpath);
		if (error)
			return fz_rethrow(error, "cannot duplicate path node");
	}
	else if (dofill)
	{
		fpath = csi->path;
	}
	else if (dostroke)
	{
		spath = csi->path;
	}
	else
	{
		fz_dropnode((fz_node*)csi->path);
	}

	csi->path = nil;

	/*
	 * Add nodes to the tree.
	 */

	if (dofill)
	{
		error = pdf_buildfillpath(gstate, fpath, evenodd);
		if (error)
		{
			reason = "cannot finish fill path";
			goto cleanup;
		}

		error = pdf_addfillshape(gstate, (fz_node*)fpath);
		if (error)
		{
			reason = "cannot add filled path";
			goto cleanup;
		}
	}

	if (dostroke)
	{
		error = pdf_buildstrokepath(gstate, spath);
		if (error)
		{
			reason = "cannot finish stroke path";
			goto cleanup;
		}

		error = pdf_addstrokeshape(gstate, (fz_node*)spath);
		if (error)
		{
			reason = "cannot add stroked path";
			goto cleanup;
		}
	}

	if (csi->clip)
	{
		error = fz_endpath(clip, evenodd ? FZ_EOFILL : FZ_FILL, nil, nil);
		if (error)
		{
			reason = "cannot finish clip path";
			goto cleanupclip;
		}

		error = pdf_addclipmask(gstate, (fz_node*)clip);
		if (error)
		{
			reason = "cannot add clip mask";
			goto cleanupclip;
		}

		csi->clip = 0;
	}

	error = fz_newpathnode(&csi->path);
	if (error)
		return fz_rethrow(error, "cannot create path node");;

	return fz_okay;

cleanup:
	if (spath) fz_dropnode((fz_node *)spath);
	if (fpath) fz_dropnode((fz_node *)fpath);
cleanupclip:
	if (clip) fz_dropnode((fz_node *)clip);

	return fz_rethrow(error, "%s", reason);
}

/*
 * Text
 */

fz_error *
pdf_flushtext(pdf_csi *csi)
{
	pdf_gstate *gstate = csi->gstate + csi->gtop;
	fz_error *error;

	if (csi->text)
	{
		switch (csi->textmode)
		{
		case 0:	/* fill */
		case 1:	/* stroke */
		case 2:	/* stroke + fill */
			error = pdf_addfillshape(gstate, (fz_node*)csi->text);
			if (error)
				return fz_rethrow(error, "cannot add filled text");
			break;

		case 3:	/* invisible */
			error = addinvisibleshape(gstate, (fz_node*)csi->text);
			if (error)
				return fz_rethrow(error, "cannot add invisible text");
			break;

		case 4: /* fill + clip */
		case 5: /* stroke + clip */
		case 6: /* stroke + fill + clip */
			{
				fz_textnode *temp;

				error = fz_clonetextnode(&temp, csi->text);
				if (error)
					return fz_rethrow(error, "cannot duplicate text");

				error = pdf_addfillshape(gstate, (fz_node*)temp);
				if (error)
				{
					fz_dropnode((fz_node*)temp);
					return fz_rethrow(error, "cannot add filled text");
				}

				/* FIXME stroked text */
			}
			/* fall through */

		case 7: /* invisible clip ( + fallthrough clips ) */
			if (!csi->textclip)
			{
				error = pdf_newovernode(&csi->textclip, gstate);
				if (error)
					return fz_rethrow(error, "cannot create over node");
			}
			fz_insertnodelast(csi->textclip, (fz_node*)csi->text);
			break;
		}

		csi->text = nil;
	}

	return fz_okay;
}

fz_error *
showglyph(pdf_csi *csi, int cid)
{
	pdf_gstate *gstate = csi->gstate + csi->gtop;
	pdf_font *font = gstate->font;
	fz_error *error;
	fz_matrix tsm, trm;
	float w0, w1, tx, ty;
	fz_hmtx h;
	fz_vmtx v;

	tsm.a = gstate->size * gstate->scale;
	tsm.b = 0;
	tsm.c = 0;
	tsm.d = gstate->size;
	tsm.e = 0;
	tsm.f = gstate->rise;

	if (font->super.wmode == 1)
	{
		v = fz_getvmtx((fz_font*)font, cid);
		tsm.e -= v.x * gstate->size / 1000.0;
		tsm.f -= v.y * gstate->size / 1000.0;
	}

	trm = fz_concat(tsm, csi->tm);

	/* flush buffered text if face or matrix or rendermode has changed */
	if (!csi->text ||
			((fz_font*)font) != csi->text->font ||
			fabs(trm.a - csi->text->trm.a) > FLT_EPSILON ||
			fabs(trm.b - csi->text->trm.b) > FLT_EPSILON ||
			fabs(trm.c - csi->text->trm.c) > FLT_EPSILON ||
			fabs(trm.d - csi->text->trm.d) > FLT_EPSILON ||
			gstate->render != csi->textmode)
	{
		error = pdf_flushtext(csi);
		if (error)
			return fz_rethrow(error, "cannot finish text node (face/matrix change)");

		error = fz_newtextnode(&csi->text, (fz_font*)font);
		if (error)
			return fz_rethrow(error, "cannot create text node");

		csi->text->trm = trm;
		csi->text->trm.e = 0;
		csi->text->trm.f = 0;
		csi->textmode = gstate->render;
	}

	/* add glyph to textobject */
	error = fz_addtext(csi->text, cid, trm.e, trm.f);
	if (error)
		return fz_rethrow(error, "cannot add glyph to text node");

	if (font->super.wmode == 0)
	{
		h = fz_gethmtx((fz_font*)font, cid);
		w0 = h.w / 1000.0;
		tx = (w0 * gstate->size + gstate->charspace) * gstate->scale;
		csi->tm = fz_concat(fz_translate(tx, 0), csi->tm);
	}
	else
	{
		w1 = v.w / 1000.0;
		ty = w1 * gstate->size + gstate->charspace;
		csi->tm = fz_concat(fz_translate(0, ty), csi->tm);
	}

	return fz_okay;
}

void
showspace(pdf_csi *csi, float tadj)
{
	pdf_gstate *gstate = csi->gstate + csi->gtop;
	pdf_font *font = gstate->font;
	if (font->super.wmode == 0)
		csi->tm = fz_concat(fz_translate(tadj * gstate->scale, 0), csi->tm);
	else
		csi->tm = fz_concat(fz_translate(0, tadj), csi->tm);
}

fz_error *
pdf_showtext(pdf_csi *csi, fz_obj *text)
{
	pdf_gstate *gstate = csi->gstate + csi->gtop;
	pdf_font *font = gstate->font;
	fz_error *error;
	unsigned char *buf;
	unsigned char *end;
	int i, len;
	int cpt, cid;

	if (fz_isarray(text))
	{
		for (i = 0; i < fz_arraylen(text); i++)
		{
			fz_obj *item = fz_arrayget(text, i);
			if (fz_isstring(item))
			{
				error = pdf_showtext(csi, item);
				if (error)
					return fz_rethrow(error, "cannot draw text item");
			}
			else
			{
				showspace(csi, - fz_toreal(item) * gstate->size / 1000.0);
			}
		}
		return fz_okay;
	}

	buf = (unsigned char *)fz_tostrbuf(text);
	len = fz_tostrlen(text);
	end = buf + len;

	while (buf < end)
	{
		buf = pdf_decodecmap(font->encoding, buf, &cpt);
		cid = pdf_lookupcmap(font->encoding, cpt);
		if (cid == -1)
			cid = 0;

		error = showglyph(csi, cid);
		if (error)
			return fz_rethrow(error, "cannot draw glyph");

		if (cpt == 32)
			showspace(csi, gstate->wordspace);
	}

	return fz_okay;
}