diff options
Diffstat (limited to 'samples/fx_lpng/lpng_v163/fx_pngtrans.c')
| -rw-r--r-- | samples/fx_lpng/lpng_v163/fx_pngtrans.c | 840 |
1 files changed, 840 insertions, 0 deletions
diff --git a/samples/fx_lpng/lpng_v163/fx_pngtrans.c b/samples/fx_lpng/lpng_v163/fx_pngtrans.c new file mode 100644 index 0000000000..0de6a46f30 --- /dev/null +++ b/samples/fx_lpng/lpng_v163/fx_pngtrans.c @@ -0,0 +1,840 @@ +/* pngtrans.c - transforms the data in a row (used by both readers and writers)
+ *
+ * Last changed in libpng 1.6.2 [April 25, 2013]
+ * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* Turn on BGR-to-RGB mapping */
+void PNGAPI
+png_set_bgr(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_bgr");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->transformations |= PNG_BGR;
+}
+#endif
+
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* Turn on 16 bit byte swapping */
+void PNGAPI
+png_set_swap(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_swap");
+
+ if (png_ptr == NULL)
+ return;
+
+ if (png_ptr->bit_depth == 16)
+ png_ptr->transformations |= PNG_SWAP_BYTES;
+}
+#endif
+
+#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+/* Turn on pixel packing */
+void PNGAPI
+png_set_packing(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_packing");
+
+ if (png_ptr == NULL)
+ return;
+
+ if (png_ptr->bit_depth < 8)
+ {
+ png_ptr->transformations |= PNG_PACK;
+ png_ptr->usr_bit_depth = 8;
+ }
+}
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+/* Turn on packed pixel swapping */
+void PNGAPI
+png_set_packswap(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_packswap");
+
+ if (png_ptr == NULL)
+ return;
+
+ if (png_ptr->bit_depth < 8)
+ png_ptr->transformations |= PNG_PACKSWAP;
+}
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+void PNGAPI
+png_set_shift(png_structrp png_ptr, png_const_color_8p true_bits)
+{
+ png_debug(1, "in png_set_shift");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->transformations |= PNG_SHIFT;
+ png_ptr->shift = *true_bits;
+}
+#endif
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
+ defined(PNG_WRITE_INTERLACING_SUPPORTED)
+int PNGAPI
+png_set_interlace_handling(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_interlace handling");
+
+ if (png_ptr && png_ptr->interlaced)
+ {
+ png_ptr->transformations |= PNG_INTERLACE;
+ return (7);
+ }
+
+ return (1);
+}
+#endif
+
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+/* Add a filler byte on read, or remove a filler or alpha byte on write.
+ * The filler type has changed in v0.95 to allow future 2-byte fillers
+ * for 48-bit input data, as well as to avoid problems with some compilers
+ * that don't like bytes as parameters.
+ */
+void PNGAPI
+png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
+{
+ png_debug(1, "in png_set_filler");
+
+ if (png_ptr == NULL)
+ return;
+
+ /* In libpng 1.6 it is possible to determine whether this is a read or write
+ * operation and therefore to do more checking here for a valid call.
+ */
+ if (png_ptr->mode & PNG_IS_READ_STRUCT)
+ {
+# ifdef PNG_READ_FILLER_SUPPORTED
+ /* On read png_set_filler is always valid, regardless of the base PNG
+ * format, because other transformations can give a format where the
+ * filler code can execute (basically an 8 or 16-bit component RGB or G
+ * format.)
+ *
+ * NOTE: usr_channels is not used by the read code! (This has led to
+ * confusion in the past.) The filler is only used in the read code.
+ */
+ png_ptr->filler = (png_uint_16)filler;
+# else
+ png_app_error(png_ptr, "png_set_filler not supported on read");
+ PNG_UNUSED(filler) /* not used in the write case */
+ return;
+# endif
+ }
+
+ else /* write */
+ {
+# ifdef PNG_WRITE_FILLER_SUPPORTED
+ /* On write the usr_channels parameter must be set correctly at the
+ * start to record the number of channels in the app-supplied data.
+ */
+ switch (png_ptr->color_type)
+ {
+ case PNG_COLOR_TYPE_RGB:
+ png_ptr->usr_channels = 4;
+ break;
+
+ case PNG_COLOR_TYPE_GRAY:
+ if (png_ptr->bit_depth >= 8)
+ {
+ png_ptr->usr_channels = 2;
+ break;
+ }
+
+ else
+ {
+ /* There simply isn't any code in libpng to strip out bits
+ * from bytes when the components are less than a byte in
+ * size!
+ */
+ png_app_error(png_ptr,
+ "png_set_filler is invalid for low bit depth gray output");
+ return;
+ }
+
+ default:
+ png_app_error(png_ptr,
+ "png_set_filler: inappropriate color type");
+ return;
+ }
+# else
+ png_app_error(png_ptr, "png_set_filler not supported on write");
+ return;
+# endif
+ }
+
+ /* Here on success - libpng supports the operation, set the transformation
+ * and the flag to say where the filler channel is.
+ */
+ png_ptr->transformations |= PNG_FILLER;
+
+ if (filler_loc == PNG_FILLER_AFTER)
+ png_ptr->flags |= PNG_FLAG_FILLER_AFTER;
+
+ else
+ png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;
+}
+
+/* Added to libpng-1.2.7 */
+void PNGAPI
+png_set_add_alpha(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
+{
+ png_debug(1, "in png_set_add_alpha");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_set_filler(png_ptr, filler, filler_loc);
+ /* The above may fail to do anything. */
+ if (png_ptr->transformations & PNG_FILLER)
+ png_ptr->transformations |= PNG_ADD_ALPHA;
+}
+
+#endif
+
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
+ defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
+void PNGAPI
+png_set_swap_alpha(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_swap_alpha");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->transformations |= PNG_SWAP_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
+ defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+void PNGAPI
+png_set_invert_alpha(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_invert_alpha");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->transformations |= PNG_INVERT_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+void PNGAPI
+png_set_invert_mono(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_invert_mono");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->transformations |= PNG_INVERT_MONO;
+}
+
+/* Invert monochrome grayscale data */
+void /* PRIVATE */
+png_do_invert(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_invert");
+
+ /* This test removed from libpng version 1.0.13 and 1.2.0:
+ * if (row_info->bit_depth == 1 &&
+ */
+ if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+ {
+ png_bytep rp = row;
+ png_size_t i;
+ png_size_t istop = row_info->rowbytes;
+
+ for (i = 0; i < istop; i++)
+ {
+ *rp = (png_byte)(~(*rp));
+ rp++;
+ }
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+ row_info->bit_depth == 8)
+ {
+ png_bytep rp = row;
+ png_size_t i;
+ png_size_t istop = row_info->rowbytes;
+
+ for (i = 0; i < istop; i += 2)
+ {
+ *rp = (png_byte)(~(*rp));
+ rp += 2;
+ }
+ }
+
+#ifdef PNG_16BIT_SUPPORTED
+ else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+ row_info->bit_depth == 16)
+ {
+ png_bytep rp = row;
+ png_size_t i;
+ png_size_t istop = row_info->rowbytes;
+
+ for (i = 0; i < istop; i += 4)
+ {
+ *rp = (png_byte)(~(*rp));
+ *(rp + 1) = (png_byte)(~(*(rp + 1)));
+ rp += 4;
+ }
+ }
+#endif
+}
+#endif
+
+#ifdef PNG_16BIT_SUPPORTED
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* Swaps byte order on 16 bit depth images */
+void /* PRIVATE */
+png_do_swap(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_swap");
+
+ if (row_info->bit_depth == 16)
+ {
+ png_bytep rp = row;
+ png_uint_32 i;
+ png_uint_32 istop= row_info->width * row_info->channels;
+
+ for (i = 0; i < istop; i++, rp += 2)
+ {
+ png_byte t = *rp;
+ *rp = *(rp + 1);
+ *(rp + 1) = t;
+ }
+ }
+}
+#endif
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+static PNG_CONST png_byte onebppswaptable[256] = {
+ 0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
+ 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
+ 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
+ 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
+ 0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4,
+ 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
+ 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC,
+ 0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
+ 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
+ 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
+ 0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA,
+ 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
+ 0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6,
+ 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
+ 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
+ 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
+ 0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1,
+ 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
+ 0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9,
+ 0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
+ 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
+ 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
+ 0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED,
+ 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
+ 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3,
+ 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
+ 0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
+ 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
+ 0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7,
+ 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
+ 0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF,
+ 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
+};
+
+static PNG_CONST png_byte twobppswaptable[256] = {
+ 0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0,
+ 0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0,
+ 0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4,
+ 0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4,
+ 0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8,
+ 0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8,
+ 0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC,
+ 0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC,
+ 0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1,
+ 0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1,
+ 0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5,
+ 0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5,
+ 0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9,
+ 0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9,
+ 0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD,
+ 0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD,
+ 0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2,
+ 0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2,
+ 0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6,
+ 0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6,
+ 0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA,
+ 0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA,
+ 0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE,
+ 0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE,
+ 0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3,
+ 0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3,
+ 0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7,
+ 0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7,
+ 0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB,
+ 0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB,
+ 0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF,
+ 0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF
+};
+
+static PNG_CONST png_byte fourbppswaptable[256] = {
+ 0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
+ 0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
+ 0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71,
+ 0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1,
+ 0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72,
+ 0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2,
+ 0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73,
+ 0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3,
+ 0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74,
+ 0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4,
+ 0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75,
+ 0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5,
+ 0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76,
+ 0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6,
+ 0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77,
+ 0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7,
+ 0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78,
+ 0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8,
+ 0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79,
+ 0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9,
+ 0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A,
+ 0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA,
+ 0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B,
+ 0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB,
+ 0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C,
+ 0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC,
+ 0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D,
+ 0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD,
+ 0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E,
+ 0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE,
+ 0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F,
+ 0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF
+};
+
+/* Swaps pixel packing order within bytes */
+void /* PRIVATE */
+png_do_packswap(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_packswap");
+
+ if (row_info->bit_depth < 8)
+ {
+ png_bytep rp;
+ png_const_bytep end, table;
+
+ end = row + row_info->rowbytes;
+
+ if (row_info->bit_depth == 1)
+ table = onebppswaptable;
+
+ else if (row_info->bit_depth == 2)
+ table = twobppswaptable;
+
+ else if (row_info->bit_depth == 4)
+ table = fourbppswaptable;
+
+ else
+ return;
+
+ for (rp = row; rp < end; rp++)
+ *rp = table[*rp];
+ }
+}
+#endif /* PNG_READ_PACKSWAP_SUPPORTED or PNG_WRITE_PACKSWAP_SUPPORTED */
+
+#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
+ defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+/* Remove a channel - this used to be 'png_do_strip_filler' but it used a
+ * somewhat weird combination of flags to determine what to do. All the calls
+ * to png_do_strip_filler are changed in 1.5.2 to call this instead with the
+ * correct arguments.
+ *
+ * The routine isn't general - the channel must be the channel at the start or
+ * end (not in the middle) of each pixel.
+ */
+void /* PRIVATE */
+png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
+{
+ png_bytep sp = row; /* source pointer */
+ png_bytep dp = row; /* destination pointer */
+ png_bytep ep = row + row_info->rowbytes; /* One beyond end of row */
+
+ /* At the start sp will point to the first byte to copy and dp to where
+ * it is copied to. ep always points just beyond the end of the row, so
+ * the loop simply copies (channels-1) channels until sp reaches ep.
+ *
+ * at_start: 0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc.
+ * nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc.
+ */
+
+ /* GA, GX, XG cases */
+ if (row_info->channels == 2)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ if (at_start) /* Skip initial filler */
+ ++sp;
+ else /* Skip initial channel and, for sp, the filler */
+ sp += 2, ++dp;
+
+ /* For a 1 pixel wide image there is nothing to do */
+ while (sp < ep)
+ *dp++ = *sp, sp += 2;
+
+ row_info->pixel_depth = 8;
+ }
+
+ else if (row_info->bit_depth == 16)
+ {
+ if (at_start) /* Skip initial filler */
+ sp += 2;
+ else /* Skip initial channel and, for sp, the filler */
+ sp += 4, dp += 2;
+
+ while (sp < ep)
+ *dp++ = *sp++, *dp++ = *sp, sp += 3;
+
+ row_info->pixel_depth = 16;
+ }
+
+ else
+ return; /* bad bit depth */
+
+ row_info->channels = 1;
+
+ /* Finally fix the color type if it records an alpha channel */
+ if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ row_info->color_type = PNG_COLOR_TYPE_GRAY;
+ }
+
+ /* RGBA, RGBX, XRGB cases */
+ else if (row_info->channels == 4)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ if (at_start) /* Skip initial filler */
+ ++sp;
+ else /* Skip initial channels and, for sp, the filler */
+ sp += 4, dp += 3;
+
+ /* Note that the loop adds 3 to dp and 4 to sp each time. */
+ while (sp < ep)
+ *dp++ = *sp++, *dp++ = *sp++, *dp++ = *sp, sp += 2;
+
+ row_info->pixel_depth = 24;
+ }
+
+ else if (row_info->bit_depth == 16)
+ {
+ if (at_start) /* Skip initial filler */
+ sp += 2;
+ else /* Skip initial channels and, for sp, the filler */
+ sp += 8, dp += 6;
+
+ while (sp < ep)
+ {
+ /* Copy 6 bytes, skip 2 */
+ *dp++ = *sp++, *dp++ = *sp++;
+ *dp++ = *sp++, *dp++ = *sp++;
+ *dp++ = *sp++, *dp++ = *sp, sp += 3;
+ }
+
+ row_info->pixel_depth = 48;
+ }
+
+ else
+ return; /* bad bit depth */
+
+ row_info->channels = 3;
+
+ /* Finally fix the color type if it records an alpha channel */
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ row_info->color_type = PNG_COLOR_TYPE_RGB;
+ }
+
+ else
+ return; /* The filler channel has gone already */
+
+ /* Fix the rowbytes value. */
+ row_info->rowbytes = dp-row;
+}
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* Swaps red and blue bytes within a pixel */
+void /* PRIVATE */
+png_do_bgr(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_bgr");
+
+ if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
+ {
+ png_uint_32 row_width = row_info->width;
+ if (row_info->bit_depth == 8)
+ {
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+ {
+ png_bytep rp;
+ png_uint_32 i;
+
+ for (i = 0, rp = row; i < row_width; i++, rp += 3)
+ {
+ png_byte save = *rp;
+ *rp = *(rp + 2);
+ *(rp + 2) = save;
+ }
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ {
+ png_bytep rp;
+ png_uint_32 i;
+
+ for (i = 0, rp = row; i < row_width; i++, rp += 4)
+ {
+ png_byte save = *rp;
+ *rp = *(rp + 2);
+ *(rp + 2) = save;
+ }
+ }
+ }
+
+#ifdef PNG_16BIT_SUPPORTED
+ else if (row_info->bit_depth == 16)
+ {
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+ {
+ png_bytep rp;
+ png_uint_32 i;
+
+ for (i = 0, rp = row; i < row_width; i++, rp += 6)
+ {
+ png_byte save = *rp;
+ *rp = *(rp + 4);
+ *(rp + 4) = save;
+ save = *(rp + 1);
+ *(rp + 1) = *(rp + 5);
+ *(rp + 5) = save;
+ }
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ {
+ png_bytep rp;
+ png_uint_32 i;
+
+ for (i = 0, rp = row; i < row_width; i++, rp += 8)
+ {
+ png_byte save = *rp;
+ *rp = *(rp + 4);
+ *(rp + 4) = save;
+ save = *(rp + 1);
+ *(rp + 1) = *(rp + 5);
+ *(rp + 5) = save;
+ }
+ }
+ }
+#endif
+ }
+}
+#endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */
+
+#if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
+ defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
+/* Added at libpng-1.5.10 */
+void /* PRIVATE */
+png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info)
+{
+ if (png_ptr->num_palette < (1 << row_info->bit_depth) &&
+ png_ptr->num_palette > 0) /* num_palette can be 0 in MNG files */
+ {
+ /* Calculations moved outside switch in an attempt to stop different
+ * compiler warnings. 'padding' is in *bits* within the last byte, it is
+ * an 'int' because pixel_depth becomes an 'int' in the expression below,
+ * and this calculation is used because it avoids warnings that other
+ * forms produced on either GCC or MSVC.
+ */
+ int padding = (-row_info->pixel_depth * row_info->width) & 7;
+ png_bytep rp = png_ptr->row_buf + row_info->rowbytes;
+
+ switch (row_info->bit_depth)
+ {
+ case 1:
+ {
+ /* in this case, all bytes must be 0 so we don't need
+ * to unpack the pixels except for the rightmost one.
+ */
+ for (; rp > png_ptr->row_buf; rp--)
+ {
+ if (*rp >> padding != 0)
+ png_ptr->num_palette_max = 1;
+ padding = 0;
+ }
+
+ break;
+ }
+
+ case 2:
+ {
+ for (; rp > png_ptr->row_buf; rp--)
+ {
+ int i = ((*rp >> padding) & 0x03);
+
+ if (i > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = i;
+
+ i = (((*rp >> padding) >> 2) & 0x03);
+
+ if (i > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = i;
+
+ i = (((*rp >> padding) >> 4) & 0x03);
+
+ if (i > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = i;
+
+ i = (((*rp >> padding) >> 6) & 0x03);
+
+ if (i > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = i;
+
+ padding = 0;
+ }
+
+ break;
+ }
+
+ case 4:
+ {
+ for (; rp > png_ptr->row_buf; rp--)
+ {
+ int i = ((*rp >> padding) & 0x0f);
+
+ if (i > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = i;
+
+ i = (((*rp >> padding) >> 4) & 0x0f);
+
+ if (i > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = i;
+
+ padding = 0;
+ }
+
+ break;
+ }
+
+ case 8:
+ {
+ for (; rp > png_ptr->row_buf; rp--)
+ {
+ if (*rp > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = (int) *rp;
+ }
+
+ break;
+ }
+
+ default:
+ break;
+ }
+ }
+}
+#endif /* PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED */
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+ defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+void PNGAPI
+png_set_user_transform_info(png_structrp png_ptr, png_voidp
+ user_transform_ptr, int user_transform_depth, int user_transform_channels)
+{
+ png_debug(1, "in png_set_user_transform_info");
+
+ if (png_ptr == NULL)
+ return;
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+ if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+ (png_ptr->flags & PNG_FLAG_ROW_INIT) != 0)
+ {
+ png_app_error(png_ptr,
+ "info change after png_start_read_image or png_read_update_info");
+ return;
+ }
+#endif
+
+ png_ptr->user_transform_ptr = user_transform_ptr;
+ png_ptr->user_transform_depth = (png_byte)user_transform_depth;
+ png_ptr->user_transform_channels = (png_byte)user_transform_channels;
+}
+#endif
+
+/* This function returns a pointer to the user_transform_ptr associated with
+ * the user transform functions. The application should free any memory
+ * associated with this pointer before png_write_destroy and png_read_destroy
+ * are called.
+ */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+png_voidp PNGAPI
+png_get_user_transform_ptr(png_const_structrp png_ptr)
+{
+ if (png_ptr == NULL)
+ return (NULL);
+
+ return png_ptr->user_transform_ptr;
+}
+#endif
+
+#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
+png_uint_32 PNGAPI
+png_get_current_row_number(png_const_structrp png_ptr)
+{
+ /* See the comments in png.h - this is the sub-image row when reading and
+ * interlaced image.
+ */
+ if (png_ptr != NULL)
+ return png_ptr->row_number;
+
+ return PNG_UINT_32_MAX; /* help the app not to fail silently */
+}
+
+png_byte PNGAPI
+png_get_current_pass_number(png_const_structrp png_ptr)
+{
+ if (png_ptr != NULL)
+ return png_ptr->pass;
+ return 8; /* invalid */
+}
+#endif /* PNG_USER_TRANSFORM_INFO_SUPPORTED */
+#endif /* PNG_READ_USER_TRANSFORM_SUPPORTED ||
+ PNG_WRITE_USER_TRANSFORM_SUPPORTED */
+#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
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