/*!
* pixcmapHasColor()
*
* Input: cmap
* &color (<return> TRUE if cmap has color; FALSE otherwise)
* Return: 0 if OK, 1 on error
*/
LEPTONICA_EXPORT l_int32
pixcmapHasColor(PIXCMAP *cmap,
l_int32 *pcolor)
{
l_int32 n, i;
l_int32 *rmap, *gmap, *bmap;
PROCNAME("pixcmapHasColor");
if (!pcolor)
return ERROR_INT("&color not defined", procName, 1);
*pcolor = FALSE;
if (!cmap)
return ERROR_INT("cmap not defined", procName, 1);
if (pixcmapToArrays(cmap, &rmap, &gmap, &bmap))
return ERROR_INT("colormap arrays not made", procName, 1);
n = pixcmapGetCount(cmap);
for (i = 0; i < n; i++) {
if ((rmap[i] != gmap[i]) || (rmap[i] != bmap[i])) {
*pcolor = TRUE;
break;
}
}
FREE(rmap);
FREE(gmap);
FREE(bmap);
return 0;
}
/*!
* pixcmapWriteStream()
*
* Input: stream, cmap
* Return: 0 if OK, 1 on error
*/
l_int32
pixcmapWriteStream(FILE *fp,
PIXCMAP *cmap)
{
l_int32 *rmap, *gmap, *bmap;
l_int32 i;
PROCNAME("pixcmapWriteStream");
if (!fp)
return ERROR_INT("stream not defined", procName, 1);
if (!cmap)
return ERROR_INT("cmap not defined", procName, 1);
if (pixcmapToArrays(cmap, &rmap, &gmap, &bmap))
return ERROR_INT("colormap arrays not made", procName, 1);
fprintf(fp, "\nPixcmap: depth = %d bpp; %d colors\n", cmap->depth, cmap->n);
fprintf(fp, "Color R-val G-val B-val\n");
fprintf(fp, "--------------------------------\n");
for (i = 0; i < cmap->n; i++)
fprintf(fp, "%3d %3d %3d %3d\n",
i, rmap[i], gmap[i], bmap[i]);
fprintf(fp, "\n");
FREE(rmap);
FREE(gmap);
FREE(bmap);
return 0;
}
int main(int argc,
char **argv)
{
l_uint8 *data;
l_int32 w, h, n1, n2, n, i, minval, maxval;
l_int32 ncolors, rval, gval, bval, equal;
l_int32 *rmap, *gmap, *bmap;
l_uint32 color;
l_float32 gamma;
BOX *box;
FILE *fp;
PIX *pix1, *pix2, *pix3, *pix4, *pix5, *pix6;
PIX *pixs, *pixb, *pixg, *pixc, *pixd;
PIX *pixg2, *pixcs1, *pixcs2, *pixd1, *pixd2;
PIXA *pixa, *pixa2, *pixa3;
PIXCMAP *cmap, *cmap2;
RGBA_QUAD *cta;
L_REGPARAMS *rp;
if (regTestSetup(argc, argv, &rp))
return 1;
/* ------------------------ (1) ----------------------------*/
/* Blend with a white background */
pix1 = pixRead("books_logo.png");
pixDisplayWithTitle(pix1, 100, 0, NULL, rp->display);
pix2 = pixAlphaBlendUniform(pix1, 0xffffff00);
pixDisplayWithTitle(pix2, 100, 150, NULL, rp->display);
regTestWritePixAndCheck(rp, pix1, IFF_PNG); /* 0 */
regTestWritePixAndCheck(rp, pix2, IFF_PNG); /* 1 */
/* Generate an alpha layer based on the white background */
pix3 = pixSetAlphaOverWhite(pix2);
pixSetSpp(pix3, 3);
pixWrite("/tmp/alphaops.2.png", pix3, IFF_PNG); /* without alpha */
regTestCheckFile(rp, "/tmp/alphaops.2.png"); /* 2 */
pixSetSpp(pix3, 4);
regTestWritePixAndCheck(rp, pix3, IFF_PNG); /* 3, with alpha */
pixDisplayWithTitle(pix3, 100, 300, NULL, rp->display);
/* Render on a light yellow background */
pix4 = pixAlphaBlendUniform(pix3, 0xffffe000);
regTestWritePixAndCheck(rp, pix4, IFF_PNG); /* 4 */
pixDisplayWithTitle(pix4, 100, 450, NULL, rp->display);
pixDestroy(&pix1);
pixDestroy(&pix2);
pixDestroy(&pix3);
pixDestroy(&pix4);
/* ------------------------ (2) ----------------------------*/
lept_rmdir("alpha");
lept_mkdir("alpha");
/* Make the transparency (alpha) layer.
* pixs is the mask. We turn it into a transparency (alpha)
* layer by converting to 8 bpp. A small convolution fuzzes
* the mask edges so that you don't see the pixels. */
pixs = pixRead("feyn-fract.tif");
pixGetDimensions(pixs, &w, &h, NULL);
pixg = pixConvert1To8(NULL, pixs, 0, 255);
pixg2 = pixBlockconvGray(pixg, NULL, 1, 1);
regTestWritePixAndCheck(rp, pixg2, IFF_JFIF_JPEG); /* 5 */
pixDisplayWithTitle(pixg2, 0, 0, "alpha", rp->display);
/* Make the viewable image.
* pixc is the image that we see where the alpha layer is
* opaque -- i.e., greater than 0. Scale it to the same
* size as the mask. To visualize what this will look like
* when displayed over a black background, create the black
* background image, pixb, and do the blending with pixcs1
* explicitly using the alpha layer pixg2. */
pixc = pixRead("tetons.jpg");
pixcs1 = pixScaleToSize(pixc, w, h);
regTestWritePixAndCheck(rp, pixcs1, IFF_JFIF_JPEG); /* 6 */
pixDisplayWithTitle(pixcs1, 300, 0, "viewable", rp->display);
pixb = pixCreateTemplate(pixcs1); /* black */
pixd1 = pixBlendWithGrayMask(pixb, pixcs1, pixg2, 0, 0);
regTestWritePixAndCheck(rp, pixd1, IFF_JFIF_JPEG); /* 7 */
pixDisplayWithTitle(pixd1, 600, 0, "alpha-blended 1", rp->display);
/* Embed the alpha layer pixg2 into the color image pixc.
* Write it out as is. Then clean pixcs1 (to 0) under the fully
* transparent part of the alpha layer, and write that result
* out as well. */
pixSetRGBComponent(pixcs1, pixg2, L_ALPHA_CHANNEL);
pixWrite("/tmp/alpha/pixcs1.png", pixcs1, IFF_PNG);
pixcs2 = pixSetUnderTransparency(pixcs1, 0, 0);
pixWrite("/tmp/alpha/pixcs2.png", pixcs2, IFF_PNG);
/* What will this look like over a black background?
* Do the blending explicitly and display. It should
* look identical to the blended result pixd1 before cleaning. */
pixd2 = pixBlendWithGrayMask(pixb, pixcs2, pixg2, 0, 0);
regTestWritePixAndCheck(rp, pixd2, IFF_JFIF_JPEG); /* 8 */
pixDisplayWithTitle(pixd2, 0, 400, "alpha blended 2", rp->display);
/* Read the two images back, ignoring the transparency layer.
* The uncleaned image will come back identical to pixcs1.
* However, the cleaned image will be black wherever
* the alpha layer was fully transparent. It will
* look the same when viewed through the alpha layer,
* but have much better compression. */
pix1 = pixRead("/tmp/alpha/pixcs1.png"); /* just pixcs1 */
pix2 = pixRead("/tmp/alpha/pixcs2.png"); /* cleaned under transparent */
n1 = nbytesInFile("/tmp/alpha/pixcs1.png");
n2 = nbytesInFile("/tmp/alpha/pixcs2.png");
fprintf(stderr, " Original: %d bytes\n Cleaned: %d bytes\n", n1, n2);
regTestWritePixAndCheck(rp, pix1, IFF_JFIF_JPEG); /* 9 */
regTestWritePixAndCheck(rp, pix2, IFF_JFIF_JPEG); /* 10 */
pixDisplayWithTitle(pix1, 300, 400, "without alpha", rp->display);
pixDisplayWithTitle(pix2, 600, 400, "cleaned under transparent",
rp->display);
pixa = pixaCreate(0);
pixSaveTiled(pixg2, pixa, 1.0, 1, 20, 32);
pixSaveTiled(pixcs1, pixa, 1.0, 1, 20, 0);
pixSaveTiled(pix1, pixa, 1.0, 0, 20, 0);
pixSaveTiled(pixd1, pixa, 1.0, 1, 20, 0);
pixSaveTiled(pixd2, pixa, 1.0, 0, 20, 0);
pixSaveTiled(pix2, pixa, 1.0, 1, 20, 0);
pixd = pixaDisplay(pixa, 0, 0);
regTestWritePixAndCheck(rp, pixd, IFF_JFIF_JPEG); /* 11 */
pixDisplayWithTitle(pixd, 200, 200, "composite", rp->display);
pixWrite("/tmp/alpha/alpha.png", pixd, IFF_JFIF_JPEG);
pixDestroy(&pixd);
pixaDestroy(&pixa);
pixDestroy(&pixs);
pixDestroy(&pixb);
pixDestroy(&pixg);
pixDestroy(&pixg2);
pixDestroy(&pixc);
pixDestroy(&pixcs1);
pixDestroy(&pixcs2);
pixDestroy(&pixd);
pixDestroy(&pixd1);
pixDestroy(&pixd2);
pixDestroy(&pix1);
pixDestroy(&pix2);
/* ------------------------ (3) ----------------------------*/
color = 0xffffa000;
gamma = 1.0;
minval = 0;
maxval = 200;
box = boxCreate(0, 85, 600, 100);
pixa = pixaCreate(6);
pix1 = pixRead("blend-green1.jpg");
pixaAddPix(pixa, pix1, L_INSERT);
pix1 = pixRead("blend-green2.png");
pixaAddPix(pixa, pix1, L_INSERT);
pix1 = pixRead("blend-green3.png");
pixaAddPix(pixa, pix1, L_INSERT);
pix1 = pixRead("blend-orange.jpg");
pixaAddPix(pixa, pix1, L_INSERT);
pix1 = pixRead("blend-yellow.jpg");
pixaAddPix(pixa, pix1, L_INSERT);
pix1 = pixRead("blend-red.png");
pixaAddPix(pixa, pix1, L_INSERT);
n = pixaGetCount(pixa);
pixa2 = pixaCreate(n);
pixa3 = pixaCreate(n);
for (i = 0; i < n; i++) {
pix1 = pixaGetPix(pixa, i, L_CLONE);
pix2 = DoBlendTest(pix1, box, color, gamma, minval, maxval, 1);
regTestWritePixAndCheck(rp, pix2, IFF_JFIF_JPEG); /* 12, 14, ... 22 */
pixDisplayWithTitle(pix2, 150 * i, 0, NULL, rp->display);
pixaAddPix(pixa2, pix2, L_INSERT);
pix2 = DoBlendTest(pix1, box, color, gamma, minval, maxval, 2);
regTestWritePixAndCheck(rp, pix2, IFF_JFIF_JPEG); /* 13, 15, ... 23 */
pixDisplayWithTitle(pix2, 150 * i, 200, NULL, rp->display);
pixaAddPix(pixa3, pix2, L_INSERT);
pixDestroy(&pix1);
}
if (rp->display) {
pixaConvertToPdf(pixa2, 0, 0.75, L_FLATE_ENCODE, 0, "blend 1 test",
"/tmp/alpha/blending1.pdf");
pixaConvertToPdf(pixa3, 0, 0.75, L_FLATE_ENCODE, 0, "blend 2 test",
"/tmp/alpha/blending2.pdf");
}
pixaDestroy(&pixa);
pixaDestroy(&pixa2);
pixaDestroy(&pixa3);
boxDestroy(&box);
/* ------------------------ (4) ----------------------------*/
/* Use one image as the alpha component for a second image */
pix1 = pixRead("test24.jpg");
pix2 = pixRead("marge.jpg");
pix3 = pixScale(pix2, 1.9, 2.2);
pix4 = pixConvertTo8(pix3, 0);
pixSetRGBComponent(pix1, pix4, L_ALPHA_CHANNEL);
regTestWritePixAndCheck(rp, pix1, IFF_PNG); /* 24 */
pixDisplayWithTitle(pix1, 600, 0, NULL, rp->display);
/* Set the alpha value in a colormap to bval */
pix5 = pixOctreeColorQuant(pix1, 128, 0);
cmap = pixGetColormap(pix5);
pixcmapToArrays(cmap, &rmap, &gmap, &bmap, NULL);
n = pixcmapGetCount(cmap);
for (i = 0; i < n; i++) {
pixcmapGetColor(cmap, i, &rval, &gval, &bval);
cta = (RGBA_QUAD *)cmap->array;
cta[i].alpha = bval;
}
/* Test binary serialization/deserialization of colormap with alpha */
pixcmapSerializeToMemory(cmap, 4, &ncolors, &data);
cmap2 = pixcmapDeserializeFromMemory(data, 4, ncolors);
CmapEqual(cmap, cmap2, &equal);
regTestCompareValues(rp, TRUE, equal, 0.0); /* 25 */
pixcmapDestroy(&cmap2);
lept_free(data);
/* Test ascii serialization/deserialization of colormap with alpha */
fp = fopenWriteStream("/tmp/alpha/cmap.4", "w");
pixcmapWriteStream(fp, cmap);
fclose(fp);
fp = fopenReadStream("/tmp/alpha/cmap.4");
cmap2 = pixcmapReadStream(fp);
fclose(fp);
CmapEqual(cmap, cmap2, &equal);
regTestCompareValues(rp, TRUE, equal, 0.0); /* 26 */
pixcmapDestroy(&cmap2);
/* Test r/w for cmapped pix with non-opaque alpha */
pixDisplayWithTitle(pix5, 900, 0, NULL, rp->display);
regTestWritePixAndCheck(rp, pix5, IFF_PNG); /* 27 */
pixWrite("/tmp/alpha/fourcomp.png", pix5, IFF_PNG);
pix6 = pixRead("/tmp/alpha/fourcomp.png");
regTestComparePix(rp, pix5, pix6); /* 28 */
pixDestroy(&pix1);
pixDestroy(&pix2);
pixDestroy(&pix3);
pixDestroy(&pix4);
pixDestroy(&pix5);
pixDestroy(&pix6);
lept_free(rmap);
lept_free(gmap);
lept_free(bmap);
return regTestCleanup(rp);
}
/*!
* pixWriteStreamPng()
*
* Input: stream
* pix
* gamma (use 0.0 if gamma is not defined)
* Return: 0 if OK; 1 on error
*
* Notes:
* (1) If called from pixWriteStream(), the stream is positioned
* at the beginning of the file.
* (2) To do sequential writes of png format images to a stream,
* use pixWriteStreamPng() directly.
* (3) gamma is an optional png chunk. If no gamma value is to be
* placed into the file, use gamma = 0.0. Otherwise, if
* gamma > 0.0, its value is written into the header.
* (4) The use of gamma in png is highly problematic. For an illuminating
* discussion, see: http://hsivonen.iki.fi/png-gamma/
* (5) What is the effect/meaning of gamma in the png file? This
* gamma, which we can call the 'source' gamma, is the
* inverse of the gamma that was used in enhance.c to brighten
* or darken images. The 'source' gamma is supposed to indicate
* the intensity mapping that was done at the time the
* image was captured. Display programs typically apply a
* 'display' gamma of 2.2 to the output, which is intended
* to linearize the intensity based on the response of
* thermionic tubes (CRTs). Flat panel LCDs have typically
* been designed to give a similar response as CRTs (call it
* "backward compatibility"). The 'display' gamma is
* in some sense the inverse of the 'source' gamma.
* jpeg encoders attached to scanners and cameras will lighten
* the pixels, applying a gamma corresponding to approximately
* a square-root relation of output vs input:
* output = input^(gamma)
* where gamma is often set near 0.4545 (1/gamma is 2.2).
* This is stored in the image file. Then if the display
* program reads the gamma, it will apply a display gamma,
* typically about 2.2; the product is 1.0, and the
* display program produces a linear output. This works because
* the dark colors were appropriately boosted by the scanner,
* as described by the 'source' gamma, so they should not
* be further boosted by the display program.
* (6) As an example, with xv and display, if no gamma is stored,
* the program acts as if gamma were 0.4545, multiplies this by 2.2,
* and does a linear rendering. Taking this as a baseline
* brightness, if the stored gamma is:
* > 0.4545, the image is rendered lighter than baseline
* < 0.4545, the image is rendered darker than baseline
* In contrast, gqview seems to ignore the gamma chunk in png.
* (7) The only valid pixel depths in leptonica are 1, 2, 4, 8, 16
* and 32. However, it is possible, and in some cases desirable,
* to write out a png file using an rgb pix that has 24 bpp.
* For example, the open source xpdf SplashBitmap class generates
* 24 bpp rgb images. Consequently, we anble writing 24 bpp pix.
* To generate such a pix, you can make a 24 bpp pix without data
* and assign the data array to the pix; e.g.,
* pix = pixCreateHeader(w, h, 24);
* pixSetData(pix, rgbdata);
* See pixConvert32To24() for an example, where we get rgbdata
* from the 32 bpp pix. Caution: do not call pixSetPadBits(),
* because the alignment is wrong and you may erase part of the
* last pixel on each line.
*/
l_int32
pixWriteStreamPng(FILE *fp,
PIX *pix,
l_float32 gamma)
{
char commentstring[] = "Comment";
l_int32 i, j, k;
l_int32 wpl, d, cmflag;
l_int32 ncolors;
l_int32 *rmap, *gmap, *bmap;
l_uint32 *data, *ppixel;
png_byte bit_depth, color_type;
png_uint_32 w, h;
png_uint_32 xres, yres;
png_bytep *row_pointers;
png_bytep rowbuffer;
png_structp png_ptr;
png_infop info_ptr;
png_colorp palette;
PIX *pixt;
PIXCMAP *cmap;
char *text;
PROCNAME("pixWriteStreamPng");
if (!fp)
return ERROR_INT("stream not open", procName, 1);
if (!pix)
return ERROR_INT("pix not defined", procName, 1);
/* Allocate the 2 data structures */
if ((png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
(png_voidp)NULL, NULL, NULL)) == NULL)
return ERROR_INT("png_ptr not made", procName, 1);
if ((info_ptr = png_create_info_struct(png_ptr)) == NULL) {
png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
return ERROR_INT("info_ptr not made", procName, 1);
}
/* Set up png setjmp error handling */
if (setjmp(png_jmpbuf(png_ptr))) {
png_destroy_write_struct(&png_ptr, &info_ptr);
return ERROR_INT("internal png error", procName, 1);
}
png_init_io(png_ptr, fp);
/* With best zlib compression (9), get between 1 and 10% improvement
* over default (5), but the compression is 3 to 10 times slower.
* Our default compression is the zlib default (5). */
png_set_compression_level(png_ptr, var_ZLIB_COMPRESSION);
w = pixGetWidth(pix);
h = pixGetHeight(pix);
d = pixGetDepth(pix);
if ((cmap = pixGetColormap(pix)))
cmflag = 1;
else
cmflag = 0;
/* Set the color type and bit depth. */
if (d == 32 && var_PNG_WRITE_ALPHA == 1) {
bit_depth = 8;
color_type = PNG_COLOR_TYPE_RGBA; /* 6 */
cmflag = 0; /* ignore if it exists */
}
else if (d == 24 || d == 32) {
bit_depth = 8;
color_type = PNG_COLOR_TYPE_RGB; /* 2 */
cmflag = 0; /* ignore if it exists */
}
else {
bit_depth = d;
color_type = PNG_COLOR_TYPE_GRAY; /* 0 */
}
if (cmflag)
color_type = PNG_COLOR_TYPE_PALETTE; /* 3 */
#if DEBUG
fprintf(stderr, "cmflag = %d, bit_depth = %d, color_type = %d\n",
cmflag, bit_depth, color_type);
#endif /* DEBUG */
png_set_IHDR(png_ptr, info_ptr, w, h, bit_depth, color_type,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE,
PNG_FILTER_TYPE_BASE);
/* Store resolution in ppm, if known */
xres = (png_uint_32)(39.37 * (l_float32)pixGetXRes(pix) + 0.5);
yres = (png_uint_32)(39.37 * (l_float32)pixGetYRes(pix) + 0.5);
if ((xres == 0) || (yres == 0))
png_set_pHYs(png_ptr, info_ptr, 0, 0, PNG_RESOLUTION_UNKNOWN);
else
png_set_pHYs(png_ptr, info_ptr, xres, yres, PNG_RESOLUTION_METER);
if (cmflag) {
pixcmapToArrays(cmap, &rmap, &gmap, &bmap);
ncolors = pixcmapGetCount(cmap);
/* Make and save the palette */
if ((palette = (png_colorp)(CALLOC(ncolors, sizeof(png_color))))
== NULL)
return ERROR_INT("palette not made", procName, 1);
for (i = 0; i < ncolors; i++) {
palette[i].red = (png_byte)rmap[i];
palette[i].green = (png_byte)gmap[i];
palette[i].blue = (png_byte)bmap[i];
}
png_set_PLTE(png_ptr, info_ptr, palette, (int)ncolors);
FREE(rmap);
FREE(gmap);
FREE(bmap);
}
/* 0.4545 is treated as the default by some image
* display programs (not gqview). A value > 0.4545 will
* lighten an image as displayed by xv, display, etc. */
if (gamma > 0.0)
png_set_gAMA(png_ptr, info_ptr, (l_float64)gamma);
if ((text = pixGetText(pix))) {
png_text text_chunk;
text_chunk.compression = PNG_TEXT_COMPRESSION_NONE;
text_chunk.key = commentstring;
text_chunk.text = text;
text_chunk.text_length = strlen(text);
#ifdef PNG_ITXT_SUPPORTED
text_chunk.itxt_length = 0;
text_chunk.lang = NULL;
text_chunk.lang_key = NULL;
#endif
png_set_text(png_ptr, info_ptr, &text_chunk, 1);
}
/* Write header and palette info */
png_write_info(png_ptr, info_ptr);
if ((d != 32) && (d != 24)) { /* not rgb color */
/* Generate a temporary pix with bytes swapped.
* For a binary image, there are two conditions in
* which you must first invert the data for writing png:
* (a) no colormap
* (b) colormap with BLACK set to 0
* png writes binary with BLACK = 0, unless contradicted
* by a colormap. If the colormap has BLACK = "1"
* (typ. about 255), do not invert the data. If there
* is no colormap, you must invert the data to store
* in default BLACK = 0 state. */
if (d == 1 &&
(!cmap || (cmap && ((l_uint8 *)(cmap->array))[0] == 0x0))) {
pixt = pixInvert(NULL, pix);
pixEndianByteSwap(pixt);
}
else
pixt = pixEndianByteSwapNew(pix);
if (!pixt) {
png_destroy_write_struct(&png_ptr, &info_ptr);
return ERROR_INT("pixt not made", procName, 1);
}
/* Make and assign array of image row pointers */
if ((row_pointers = (png_bytep *)CALLOC(h, sizeof(png_bytep))) == NULL)
return ERROR_INT("row-pointers not made", procName, 1);
wpl = pixGetWpl(pixt);
data = pixGetData(pixt);
for (i = 0; i < h; i++)
row_pointers[i] = (png_bytep)(data + i * wpl);
png_set_rows(png_ptr, info_ptr, row_pointers);
/* Transfer the data */
png_write_image(png_ptr, row_pointers);
png_write_end(png_ptr, info_ptr);
if (cmflag)
FREE(palette);
FREE(row_pointers);
pixDestroy(&pixt);
png_destroy_write_struct(&png_ptr, &info_ptr);
return 0;
}
/* For rgb, compose and write a row at a time */
data = pixGetData(pix);
wpl = pixGetWpl(pix);
if (d == 24) { /* See note 7 above: special case of 24 bpp rgb */
for (i = 0; i < h; i++) {
ppixel = data + i * wpl;
png_write_rows(png_ptr, (png_bytepp)&ppixel, 1);
}
}
else { /* 32 bpp rgb and rgba */
if ((rowbuffer = (png_bytep)CALLOC(w, 4)) == NULL)
return ERROR_INT("rowbuffer not made", procName, 1);
for (i = 0; i < h; i++) {
ppixel = data + i * wpl;
for (j = k = 0; j < w; j++) {
rowbuffer[k++] = GET_DATA_BYTE(ppixel, COLOR_RED);
rowbuffer[k++] = GET_DATA_BYTE(ppixel, COLOR_GREEN);
rowbuffer[k++] = GET_DATA_BYTE(ppixel, COLOR_BLUE);
if (var_PNG_WRITE_ALPHA == 1)
rowbuffer[k++] = GET_DATA_BYTE(ppixel, L_ALPHA_CHANNEL);
ppixel++;
}
png_write_rows(png_ptr, &rowbuffer, 1);
}
FREE(rowbuffer);
}
png_write_end(png_ptr, info_ptr);
if (cmflag)
FREE(palette);
png_destroy_write_struct(&png_ptr, &info_ptr);
return 0;
}
/*!
* pixWriteStreamJpeg()
*
* Input: stream
* pix (8 or 32 bpp)
* quality (1 - 100; 75 is default value; 0 is also default)
* progressive (0 for baseline sequential; 1 for progressive)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) Under the covers, the library transforms rgb to a
* luminence-chromaticity triple, each component of which is
* also 8 bits, and compresses that. It uses 2 Huffman tables,
* a higher resolution one (with more quantization levels)
* for luminosity and a lower resolution one for the chromas.
* (2) Progressive encoding gives better compression, at the
* expense of slower encoding and decoding.
* (3) Standard chroma subsampling is 2x2 on both the U and V
* channels. For highest quality, use no subsampling. This
* option is set by l_jpegSetNoChromaSampling(1).
* (4) There are three possibilities:
* * Grayscale image, no colormap: compress as 8 bpp image.
* * rgb full color image: copy each line into the color
* line buffer, and compress as three 8 bpp images.
* * 8 bpp colormapped image: convert each line to three
* 8 bpp line images in the color line buffer, and
* compress as three 8 bpp images.
* (5) The only valid pixel depths in leptonica are 1, 2, 4, 8, 16
* and 32 bpp. However, it is possible, and in some cases desirable,
* to write out a jpeg file using an rgb pix that has 24 bpp.
* This can be created by appending the raster data for a 24 bpp
* image (with proper scanline padding) directly to a 24 bpp
* pix that was created without a data array. See note in
* pixWriteStreamPng() for an example.
*/
l_int32
pixWriteStreamJpeg(FILE *fp,
PIX *pix,
l_int32 quality,
l_int32 progressive)
{
l_uint8 byteval;
l_int32 xres, yres;
l_int32 i, j, k;
l_int32 w, h, d, wpl, spp, colorflg, rowsamples;
l_int32 *rmap, *gmap, *bmap;
l_uint32 *ppixel, *line, *data;
JSAMPROW rowbuffer;
PIXCMAP *cmap;
struct jpeg_compress_struct cinfo;
struct jpeg_error_mgr jerr;
const char *text;
PROCNAME("pixWriteStreamJpeg");
if (!fp)
return ERROR_INT("stream not open", procName, 1);
if (!pix)
return ERROR_INT("pix not defined", procName, 1);
rewind(fp);
if (setjmp(jpeg_jmpbuf)) {
FREE(rowbuffer);
if (colorflg == 1) {
FREE(rmap);
FREE(gmap);
FREE(bmap);
}
return ERROR_INT("internal jpeg error", procName, 1);
}
rowbuffer = NULL;
rmap = NULL;
gmap = NULL;
bmap = NULL;
pixGetDimensions(pix, &w, &h, &d);
if (d != 8 && d != 24 && d != 32)
return ERROR_INT("bpp must be 8, 24 or 32", procName, 1);
if (quality <= 0)
quality = 75; /* default */
if (d == 32 || d == 24)
colorflg = 2; /* rgb; no colormap */
else if ((cmap = pixGetColormap(pix)) == NULL)
colorflg = 0; /* 8 bpp grayscale; no colormap */
else {
colorflg = 1; /* 8 bpp; colormap */
pixcmapToArrays(cmap, &rmap, &gmap, &bmap);
}
cinfo.err = jpeg_std_error(&jerr);
jerr.error_exit = jpeg_error_do_not_exit; /* catch error; do not exit! */
jpeg_create_compress(&cinfo);
jpeg_stdio_dest(&cinfo, fp);
cinfo.image_width = w;
cinfo.image_height = h;
if (colorflg == 0) {
cinfo.input_components = 1;
cinfo.in_color_space = JCS_GRAYSCALE;
}
else { /* colorflg == 1 or 2 */
cinfo.input_components = 3;
cinfo.in_color_space = JCS_RGB;
}
jpeg_set_defaults(&cinfo);
/* Setting optimize_coding to TRUE seems to improve compression
* by approx 2-4 percent, and increases comp time by approx 20%. */
cinfo.optimize_coding = FALSE;
xres = pixGetXRes(pix);
yres = pixGetYRes(pix);
if ((xres != 0) && (yres != 0)) {
cinfo.density_unit = 1; /* designates pixels per inch */
cinfo.X_density = xres;
cinfo.Y_density = yres;
}
/* Set the quality and progressive parameters */
jpeg_set_quality(&cinfo, quality, TRUE);
if (progressive) {
jpeg_simple_progression(&cinfo);
}
/* Set the chroma subsampling parameters. This is done in
* YUV color space. The Y (intensity) channel is never subsampled.
* The standard subsampling is 2x2 on both the U and V channels.
* Notation on this is confusing. For a nice illustrations, see
* http://en.wikipedia.org/wiki/Chroma_subsampling
* The standard subsampling is written as 4:2:0.
* We allow high quality where there is no subsampling on the
* chroma channels: denoted as 4:4:4. */
if (var_JPEG_NO_CHROMA_SAMPLING == 1) {
cinfo.comp_info[0].h_samp_factor = 1;
cinfo.comp_info[0].v_samp_factor = 1;
cinfo.comp_info[1].h_samp_factor = 1;
cinfo.comp_info[1].v_samp_factor = 1;
cinfo.comp_info[2].h_samp_factor = 1;
cinfo.comp_info[2].v_samp_factor = 1;
}
jpeg_start_compress(&cinfo, TRUE);
if ((text = pixGetText(pix))) {
jpeg_write_marker(&cinfo, JPEG_COM, (const JOCTET *)text, strlen(text));
}
/* Allocate row buffer */
spp = cinfo.input_components;
rowsamples = spp * w;
if ((rowbuffer = (JSAMPROW)CALLOC(sizeof(JSAMPLE), rowsamples)) == NULL)
return ERROR_INT("calloc fail for rowbuffer", procName, 1);
data = pixGetData(pix);
wpl = pixGetWpl(pix);
for (i = 0; i < h; i++) {
line = data + i * wpl;
if (colorflg == 0) { /* 8 bpp gray */
for (j = 0; j < w; j++)
rowbuffer[j] = GET_DATA_BYTE(line, j);
}
else if (colorflg == 1) { /* 8 bpp colormapped */
for (j = 0; j < w; j++) {
byteval = GET_DATA_BYTE(line, j);
rowbuffer[3 * j + COLOR_RED] = rmap[byteval];
rowbuffer[3 * j + COLOR_GREEN] = gmap[byteval];
rowbuffer[3 * j + COLOR_BLUE] = bmap[byteval];
}
}
else { /* colorflg == 2 */
if (d == 24) { /* See note 4 above; special case of 24 bpp rgb */
jpeg_write_scanlines(&cinfo, (JSAMPROW *)&line, 1);
}
else { /* standard 32 bpp rgb */
ppixel = line;
for (j = k = 0; j < w; j++) {
rowbuffer[k++] = GET_DATA_BYTE(ppixel, COLOR_RED);
rowbuffer[k++] = GET_DATA_BYTE(ppixel, COLOR_GREEN);
rowbuffer[k++] = GET_DATA_BYTE(ppixel, COLOR_BLUE);
ppixel++;
}
}
}
if (d != 24)
jpeg_write_scanlines(&cinfo, &rowbuffer, 1);
}
jpeg_finish_compress(&cinfo);
FREE(rowbuffer);
if (colorflg == 1) {
FREE(rmap);
FREE(gmap);
FREE(bmap);
}
jpeg_destroy_compress(&cinfo);
return 0;
}
