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Rework pdfioFileCreateImageObjFromData to have a separate alpha argument so

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that CMYK images can be supported.

Add unit tests.
This commit is contained in:
Michael R Sweet
2021-07-18 09:23:39 -04:00
parent 014c5dccba
commit 3e0507ba6c
3 changed files with 241 additions and 39 deletions
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82
pdfio-content.c
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@@ -1641,8 +1641,9 @@ pdfioFileCreateImageObjFromData(
const unsigned char *data, // I - Pointer to image data
size_t width, // I - Width of image
size_t height, // I - Height of image
int num_colors, // I - Number of colors
size_t num_colors, // I - Number of colors
pdfio_array_t *color_data, // I - Colorspace data or `NULL` for default
bool alpha, // I - `true` if data contains an alpha channel
bool interpolate) // I - Interpolate image data?
{
pdfio_dict_t *dict, // Image dictionary
@@ -1652,24 +1653,34 @@ pdfioFileCreateImageObjFromData(
// Mask image object, if any
pdfio_stream_t *st; // Image stream
size_t x, y, // X and Y position in image
bpp, // Bytes per pixel
linelen; // Line length
const unsigned char *dataptr; // Pointer into image data
unsigned char *line = NULL, // Current line
*lineptr; // Pointer into line
static const char *defcolors[] = // Default ColorSpace values
{
NULL,
"DeviceGray",
NULL,
"DeviceRGB",
"DeviceCMYK"
};
// Range check input...
if (!pdf || !data || !width || !height || num_colors < 1 || num_colors > 4)
if (!pdf || !data || !width || !height || num_colors < 1 || num_colors == 2 || num_colors > 4)
return (NULL);
// Allocate memory for one line of data...
linelen = (num_colors < 3 ? 1 : 3) * width;
bpp = alpha ? num_colors + 1 : num_colors;
linelen = num_colors * width;
if ((line = malloc(linelen)) == NULL)
return (NULL);
// Generate a mask image, as needed...
if (!(num_colors & 1))
if (alpha)
{
// Create the image mask dictionary...
if ((dict = pdfioDictCreate(pdf)) == NULL)
@@ -1711,9 +1722,9 @@ pdfioFileCreateImageObjFromData(
return (NULL);
}
for (y = height, dataptr = data + num_colors - 1; y > 0; y --)
for (y = height, dataptr = data + num_colors; y > 0; y --)
{
for (x = width, lineptr = line; x > 0; x --, dataptr += num_colors)
for (x = width, lineptr = line; x > 0; x --, dataptr += bpp)
*lineptr++ = *dataptr;
pdfioStreamWrite(st, line, width);
@@ -1739,7 +1750,7 @@ pdfioFileCreateImageObjFromData(
if (color_data)
pdfioDictSetArray(dict, "ColorSpace", color_data);
else
pdfioDictSetArray(dict, "ColorSpace", pdfioArrayCreateColorFromMatrix(pdf, num_colors < 3 ? 1 : 3, pdfioSRGBGamma, pdfioSRGBMatrix, pdfioSRGBWhitePoint));
pdfioDictSetName(dict, "ColorSpace", defcolors[num_colors]);
if (mask_obj)
pdfioDictSetObj(dict, "SMask", mask_obj);
@@ -1751,7 +1762,7 @@ pdfioFileCreateImageObjFromData(
}
pdfioDictSetNumber(decode, "BitsPerComponent", 8);
pdfioDictSetNumber(decode, "Colors", num_colors < 3 ? 1 : 3);
pdfioDictSetNumber(decode, "Colors", num_colors);
pdfioDictSetNumber(decode, "Columns", width);
pdfioDictSetNumber(decode, "Predictor", _PDFIO_PREDICTOR_PNG_AUTO);
pdfioDictSetDict(dict, "DecodeParms", decode);
@@ -1771,30 +1782,39 @@ pdfioFileCreateImageObjFromData(
for (y = height, dataptr = data; y > 0; y --)
{
switch (num_colors)
if (alpha)
{
case 1 :
pdfioStreamWrite(st, dataptr, linelen);
dataptr += linelen;
break;
case 2 :
for (x = width, lineptr = line; x > 0; x --, dataptr += num_colors)
*lineptr++ = *dataptr;
pdfioStreamWrite(st, line, linelen);
break;
case 3 :
pdfioStreamWrite(st, dataptr, linelen);
dataptr += linelen;
break;
case 4 :
for (x = width, lineptr = line; x > 0; x --, dataptr += num_colors)
{
*lineptr++ = dataptr[0];
*lineptr++ = dataptr[1];
*lineptr++ = dataptr[2];
}
pdfioStreamWrite(st, line, linelen);
break;
switch (num_colors)
{
case 1 :
for (x = width, lineptr = line; x > 0; x --, dataptr += bpp)
*lineptr++ = *dataptr;
break;
case 3 :
for (x = width, lineptr = line; x > 0; x --, dataptr += bpp)
{
*lineptr++ = dataptr[0];
*lineptr++ = dataptr[1];
*lineptr++ = dataptr[2];
}
break;
case 4 :
for (x = width, lineptr = line; x > 0; x --, dataptr += bpp)
{
*lineptr++ = dataptr[0];
*lineptr++ = dataptr[1];
*lineptr++ = dataptr[2];
*lineptr++ = dataptr[3];
}
break;
}
pdfioStreamWrite(st, line, linelen);
}
else
{
pdfioStreamWrite(st, dataptr, linelen);
dataptr += linelen;
}
}