postscript.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

#if 0 /* defined(DEBUG) */
	fprintf(pDiag->pOutFile,
	"(FOOTER: FileOffset 0x%04lx-0x%04lx; Bottom %ld-%ld) show\n",
		ulCharPos2FileOffset(pFtrInfo->ulCharPosStart),
		ulCharPos2FileOffset(pFtrInfo->ulCharPosNext),
		pDiag->lYtop,
		pFtrInfo->lHeight + PS_BOTTOM_MARGIN);
#endif
	vAddHdrFtr(pDiag, pFtrInfo);
	bInFtrSpace = FALSE;
} /* end of vAddFooter */

/*
 * vMove2NextPage - move to the start of the next page
 */
static void
vMove2NextPage(diagram_type *pDiag, BOOL bNewSection)
{
	fail(pDiag == NULL);

	vAddFooter(pDiag);
	fprintf(pDiag->pOutFile, "showpage\n");
	iPageCount++;
	fprintf(pDiag->pOutFile, "%%%%Page: %d %d\n", iPageCount, iPageCount);
	if (bNewSection) {
		iSectionIndex++;
		bFirstInSection = TRUE;
	}
	vAddPageSetup(pDiag->pOutFile);
	pDiag->lYtop = lPageHeight - PS_TOP_MARGIN;
	lYtopCurr = -1;
	vAddHeader(pDiag);
} /* end of vMove2NextPage */

/*
 * vMoveTo - move to the specified X,Y coordinates
 *
 * Move the current position of the specified diagram to its X,Y coordinates,
 * start on a new page if needed
 */
static void
vMoveTo(diagram_type *pDiag, long lLastVerticalMovement)
{
	fail(pDiag == NULL);
	fail(pDiag->pOutFile == NULL);

	if (pDiag->lYtop <= lFooterHeight + PS_BOTTOM_MARGIN && !bInFtrSpace) {
		vMove2NextPage(pDiag, FALSE);
		/* Repeat the last vertical movement on the new page */
		pDiag->lYtop -= lLastVerticalMovement;
	}

	fail(pDiag->lYtop < lFooterHeight + PS_BOTTOM_MARGIN && !bInFtrSpace);
	DBG_DEC_C(pDiag->lYtop < PS_BOTTOM_MARGIN, pDiag->lYtop);
	fail(pDiag->lYtop < PS_BOTTOM_MARGIN / 3);

	if (pDiag->lYtop != lYtopCurr) {
		fprintf(pDiag->pOutFile, "%.2f %.2f moveto\n",
			dDrawUnits2Points(pDiag->lXleft + PS_LEFT_MARGIN),
			dDrawUnits2Points(pDiag->lYtop));
		lYtopCurr = pDiag->lYtop;
	}
} /* end of vMoveTo */

/*
 * vProloguePS - set options and perform the PostScript initialization
 */
void
vProloguePS(diagram_type *pDiag,
	const char *szTask, const char *szFilename,
	const options_type *pOptions)
{
	FILE	*pOutFile;
	const char	*szTmp;
	time_t	tTime;

	fail(pDiag == NULL);
	fail(pDiag->pOutFile == NULL);
	fail(szTask == NULL || szTask[0] == '\0');
	fail(pOptions == NULL);

	pOutFile = pDiag->pOutFile;

	bUseLandscape = pOptions->bUseLandscape;
	eEncoding = pOptions->eEncoding;
	eImageLevel = pOptions->eImageLevel;

	if (pOptions->iPageHeight == INT_MAX) {
		lPageHeight = LONG_MAX;
	} else {
		lPageHeight = lPoints2DrawUnits(pOptions->iPageHeight);
	}
	DBG_DEC(lPageHeight);
	if (pOptions->iPageWidth == INT_MAX) {
		lPageWidth = LONG_MAX;
	} else {
		lPageWidth = lPoints2DrawUnits(pOptions->iPageWidth);
	}
	DBG_DEC(lPageWidth);
	lFooterHeight = 0;
	bInFtrSpace = FALSE;

	tFontRefCurr = (drawfile_fontref)-1;
	usFontSizeCurr = 0;
	iFontColorCurr = -1;
	lYtopCurr = -1;
	iPageCount = 0;
	iImageCount = 0;
	iSectionIndex = 0;
	bFirstInSection = TRUE;
	pDiag->lXleft = 0;
	pDiag->lYtop = lPageHeight - PS_TOP_MARGIN;

	szCreator = szTask;

	fprintf(pOutFile, "%%!PS-Adobe-2.0\n");
	fprintf(pOutFile, "%%%%Title: %s\n", szBasename(szFilename));
	fprintf(pOutFile, "%%%%Creator: %s %s\n", szCreator, VERSIONSTRING);
	szTmp = getenv("LOGNAME");
	if (szTmp == NULL || szTmp[0] == '\0') {
		szTmp = getenv("USER");
		if (szTmp == NULL || szTmp[0] == '\0') {
			szTmp = "unknown";
		}
	}
	fprintf(pOutFile, "%%%%For: %.50s\n", szTmp);
	errno = 0;
	tTime = time(NULL);
	if (tTime == (time_t)-1 && errno != 0) {
		szCreationDate = NULL;
	} else {
		szCreationDate = ctime(&tTime);
	}
	if (szCreationDate == NULL || szCreationDate[0] == '\0') {
		szCreationDate = "unknown\n";
	}
	fprintf(pOutFile, "%%%%CreationDate: %s", szCreationDate);
	if (bUseLandscape) {
		fprintf(pOutFile, "%%%%Orientation: Landscape\n");
		fprintf(pOutFile, "%%%%BoundingBox: 0 0 %.0f %.0f\n",
				dDrawUnits2Points(lPageHeight),
				dDrawUnits2Points(lPageWidth));
	} else {
		fprintf(pOutFile, "%%%%Orientation: Portrait\n");
		fprintf(pOutFile, "%%%%BoundingBox: 0 0 %.0f %.0f\n",
				dDrawUnits2Points(lPageWidth),
				dDrawUnits2Points(lPageHeight));
	}
} /* end of vProloguePS */

/*
 * vEpiloguePS - clean up after everything is done
 */
void
vEpiloguePS(diagram_type *pDiag)
{
	fail(pDiag == NULL);
	fail(pDiag->pOutFile == NULL);

	if (pDiag->lYtop < lPageHeight - PS_TOP_MARGIN) {
		vAddFooter(pDiag);
		fprintf(pDiag->pOutFile, "showpage\n");
	}
	fprintf(pDiag->pOutFile, "%%%%Trailer\n");
	fprintf(pDiag->pOutFile, "%%%%Pages: %d\n", iPageCount);
	fprintf(pDiag->pOutFile, "%%%%EOF\n");
	szCreationDate = NULL;
	szCreator = NULL;
} /* end of vEpiloguePS */

/*
 * vPrintPalette - print a postscript palette
 */
static void
vPrintPalette(FILE *pOutFile, const imagedata_type *pImg)
{
	int	iIndex;

	fail(pOutFile == NULL);
	fail(pImg == NULL);
	fail(pImg->iColorsUsed < 2);
	fail(pImg->iColorsUsed > 256);

	fprintf(pOutFile, "[ /Indexed\n");
	fprintf(pOutFile, "\t/Device%s %d\n",
		pImg->bColorImage ? "RGB" : "Gray", pImg->iColorsUsed - 1);
	fprintf(pOutFile, "<");
	for (iIndex = 0; iIndex < pImg->iColorsUsed; iIndex++) {
		fprintf(pOutFile, "%02x",
				(unsigned int)pImg->aucPalette[iIndex][0]);
		if (pImg->bColorImage) {
			fprintf(pOutFile, "%02x%02x",
				(unsigned int)pImg->aucPalette[iIndex][1],
				(unsigned int)pImg->aucPalette[iIndex][2]);
		}
		if (iIndex % 8 == 7) {
			fprintf(pOutFile, "\n");
		} else {
			fprintf(pOutFile, " ");
		}
	}
	fprintf(pOutFile, ">\n");
	fprintf(pOutFile, "] setcolorspace\n");
} /* end of vPrintPalette */

/*
 * vImageProloguePS - perform the Encapsulated PostScript initialization
 */
void
vImageProloguePS(diagram_type *pDiag, const imagedata_type *pImg)
{
	FILE	*pOutFile;

	fail(pDiag == NULL);
	fail(pDiag->pOutFile == NULL);
	fail(pImg == NULL);

	if (pImg->iVerSizeScaled <= 0 || pImg->iHorSizeScaled <= 0) {
		return;
	}

	fail(szCreationDate == NULL);
	fail(szCreator == NULL);
	fail(eImageLevel == level_no_images);

	iImageCount++;

	DBG_DEC_C(pDiag->lXleft != 0, pDiag->lXleft);

	pDiag->lYtop -= lPoints2DrawUnits(pImg->iVerSizeScaled);
	vMoveTo(pDiag, lPoints2DrawUnits(pImg->iVerSizeScaled));

	pOutFile = pDiag->pOutFile;

	fprintf(pOutFile, "BeginEPSF\n");
	fprintf(pOutFile, "%%%%BeginDocument: image%03d.eps\n", iImageCount);
	fprintf(pOutFile, "%%!PS-Adobe-2.0 EPSF-2.0\n");
	fprintf(pOutFile, "%%%%Creator: %s %s\n", szCreator, VERSIONSTRING);
	fprintf(pOutFile, "%%%%Title: Image %03d\n", iImageCount);
	fprintf(pOutFile, "%%%%CreationDate: %s", szCreationDate);
	fprintf(pOutFile, "%%%%BoundingBox: 0 0 %d %d\n",
				pImg->iHorSizeScaled, pImg->iVerSizeScaled);
	fprintf(pOutFile, "%%%%DocumentData: Clean7Bit\n");
	fprintf(pOutFile, "%%%%LanguageLevel: 2\n");
	fprintf(pOutFile, "%%%%EndComments\n");
	fprintf(pOutFile, "%%%%BeginProlog\n");
	fprintf(pOutFile, "%%%%EndProlog\n");
	fprintf(pOutFile, "%%%%Page: 1 1\n");

	fprintf(pOutFile, "save\n");

	switch (pImg->eImageType) {
	case imagetype_is_jpeg:
		fprintf(pOutFile, "/Data1 currentfile ");
		fprintf(pOutFile, "/ASCII85Decode filter def\n");
		fprintf(pOutFile, "/Data Data1 << ");
		fprintf(pOutFile, ">> /DCTDecode filter def\n");
		switch (pImg->iComponents) {
		case 1:
			fprintf(pOutFile, "/DeviceGray setcolorspace\n");
			break;
		case 3:
			fprintf(pOutFile, "/DeviceRGB setcolorspace\n");
			break;
		case 4:
			fprintf(pOutFile, "/DeviceCMYK setcolorspace\n");
			break;
		default:
			DBG_DEC(pImg->iComponents);
			break;
		}
		break;
	case imagetype_is_png:
		if (eImageLevel == level_gs_special) {
			fprintf(pOutFile,
			"/Data2 currentfile /ASCII85Decode filter def\n");
			fprintf(pOutFile,
			"/Data1 Data2 << >> /FlateDecode filter def\n");
			fprintf(pOutFile, "/Data Data1 <<\n");
			fprintf(pOutFile, "\t/Colors %d\n", pImg->iComponents);
			fprintf(pOutFile, "\t/BitsPerComponent %u\n",
						pImg->uiBitsPerComponent);
			fprintf(pOutFile, "\t/Columns %d\n", pImg->iWidth);
			fprintf(pOutFile,
				">> /PNGPredictorDecode filter def\n");
		} else {
			fprintf(pOutFile,
			"/Data1 currentfile /ASCII85Decode filter def\n");
			fprintf(pOutFile,
			"/Data Data1 << >> /FlateDecode filter def\n");
		}
		if (pImg->iComponents == 3 || pImg->iComponents == 4) {
			fprintf(pOutFile, "/DeviceRGB setcolorspace\n");
		} else if (pImg->iColorsUsed > 0) {
			vPrintPalette(pOutFile, pImg);
		} else {
			fprintf(pOutFile, "/DeviceGray setcolorspace\n");
		}
		break;
	case imagetype_is_dib:
		fprintf(pOutFile, "/Data currentfile ");
		fprintf(pOutFile, "/ASCII85Decode filter def\n");
		if (pImg->uiBitsPerComponent <= 8) {
			vPrintPalette(pOutFile, pImg);
		} else {
			fprintf(pOutFile, "/DeviceRGB setcolorspace\n");
		}
		break;
	default:
		fprintf(pOutFile, "/Data currentfile ");
		fprintf(pOutFile, "/ASCIIHexDecode filter def\n");
		fprintf(pOutFile, "/Device%s setcolorspace\n",
			pImg->bColorImage ? "RGB" : "Gray");
		break;
	}

	/* Translate to lower left corner of image */
	fprintf(pOutFile, "%.2f %.2f translate\n",
			dDrawUnits2Points(pDiag->lXleft + PS_LEFT_MARGIN),
			dDrawUnits2Points(pDiag->lYtop));

	fprintf(pOutFile, "%d %d scale\n",
				pImg->iHorSizeScaled, pImg->iVerSizeScaled);

	fprintf(pOutFile, "{ <<\n");
	fprintf(pOutFile, "\t/ImageType 1\n");
	fprintf(pOutFile, "\t/Width %d\n", pImg->iWidth);
	fprintf(pOutFile, "\t/Height %d\n", pImg->iHeight);
	if (pImg->eImageType == imagetype_is_dib) {
		/* Scanning from left to right and bottom to top */
		fprintf(pOutFile, "\t/ImageMatrix [ %d 0 0 %d 0 0 ]\n",
			pImg->iWidth, pImg->iHeight);
	} else {
		/* Scanning from left to right and top to bottom */
		fprintf(pOutFile, "\t/ImageMatrix [ %d 0 0 %d 0 %d ]\n",
			pImg->iWidth, -pImg->iHeight, pImg->iHeight);
	}
	fprintf(pOutFile, "\t/DataSource Data\n");

	switch (pImg->eImageType) {
	case imagetype_is_jpeg:
		fprintf(pOutFile, "\t/BitsPerComponent 8\n");
		switch (pImg->iComponents) {
		case 1:
			fprintf(pOutFile, "\t/Decode [0 1]\n");
			break;
		case 3:
			fprintf(pOutFile, "\t/Decode [0 1 0 1 0 1]\n");
			break;
		case 4:
			if (pImg->bAdobe) {
				/*
				 * Adobe-conforming CMYK file
				 * applying workaround for color inversion
				 */
				fprintf(pOutFile,
					"\t/Decode [1 0 1 0 1 0 1 0]\n");
			} else {
				fprintf(pOutFile,
					"\t/Decode [0 1 0 1 0 1 0 1]\n");
			}
			break;
		default:
			DBG_DEC(pImg->iComponents);
			break;
		}
		break;
	case imagetype_is_png:
		if (pImg->iComponents == 3) {
			fprintf(pOutFile, "\t/BitsPerComponent 8\n");
			fprintf(pOutFile, "\t/Decode [0 1 0 1 0 1]\n");
		} else if (pImg->iColorsUsed > 0) {
			fail(pImg->uiBitsPerComponent > 8);
			fprintf(pOutFile, "\t/BitsPerComponent %u\n",
					pImg->uiBitsPerComponent);
			fprintf(pOutFile, "\t/Decode [0 %d]\n",
					(1 << pImg->uiBitsPerComponent) - 1);
		} else {
			fprintf(pOutFile, "\t/BitsPerComponent 8\n");
			fprintf(pOutFile, "\t/Decode [0 1]\n");
		}
		break;
	case imagetype_is_dib:
		fprintf(pOutFile, "\t/BitsPerComponent 8\n");
		if (pImg->uiBitsPerComponent <= 8) {
			fprintf(pOutFile, "\t/Decode [0 255]\n");
		} else {
			fprintf(pOutFile, "\t/Decode [0 1 0 1 0 1]\n");
		}
		break;