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[libpng17] Moved READ_GAMMA to pngrtran.c. This makes everything in pngrtrans.c
depend on READ_TRANSFORMS and moves all the transform gamma (READ_GAMMA) code from elsewhere to png_tran.c. There are no code changes. There is one remaining use of the gamma (16-bit) code in the simplified API in pngread.c but that is because of a long-standing libpng bug, namely that the gamma corrected palette is no produced by png_read_update_info (John Bowler).
This commit is contained in:
John Bowler
committed by
Glenn Randers-Pehrson
Glenn Randers-Pehrson
parent
77476d3c37
commit
1a9eb510eb
121
pngpriv.h
121
pngpriv.h
@@ -935,54 +935,6 @@ PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
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extern "C" {
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#endif /* __cplusplus */
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#if defined (PNG_READ_TRANSFORMS_SUPPORTED) ||\
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defined (PNG_WRITE_TRANSFORMS_SUPPORTED)
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/* Transform support. Prior to 1.7.0 the internal transform routines (not the
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* APIs) took a png_row_infop, like the user transform function, but without
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* the png_ptr because it was never used. In 1.7.0 a separate internal
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* structure is used in place of this to allow both future development to
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* change the structure.
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*
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* The values in this structure will normally be changed by transformation
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* implementations.
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*/
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typedef struct
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{
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png_const_structrp png_ptr; /* png_struct for error handling and some
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* transform parameters.
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*/
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png_uint_32 width; /* width of row */
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unsigned int channels; /* number of channels (1, 2, 3, or 4) */
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unsigned int bit_depth; /* bit depth of row */
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unsigned int flags; /* As below */
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# define PNG_INDEXED 1 /* Indexed/palette PNG */
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# define PNG_RGB_SWAPPED 2 /* as in the PNG_BGR transformation */
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# define PNG_FILLER_IN_ALPHA 4 /* 'alpha' channel is really just a filler */
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# define PNG_ALPHA_SWAPPED 8 /* Alpha is in the first channel */
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# define PNG_ALPHA_INVERTED 16 /* Alpha values inverted */
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# define PNG_INVERTED 32 /* grayscale channel inverted */
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# define PNG_BITS_SHIFTED 64 /* Channels not in range 1..(bit_depth-1) */
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# define PNG_BYTE_SWAPPED 128 /* 'swab', i.e. pairs of bytes swapped */
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# define PNG_PIXEL_SWAPPED 256 /* pixels swapped within bytes */
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# define PNG_BAD_INDEX 512 /* Bad palette image index */
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} png_transform_control, *png_transform_controlp;
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/* Validation: channels and bit_depth can be set to anything required by
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* the transform, but the result may not be encodable in PNG. PNG_USURPED
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* must be set in this case. This macro detects the detectably unrepresentable
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* case channels case.
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*
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* Channels: must be 1 when PNG_INDEXED is set, must be 1-4 otherwise, so:
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*
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* (channels-1) <= (((flags & PNG_INDEXED)-1) & 3)
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*/
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#define PNG_VALID_CHANNELS(ri)\
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(((ri)->channels-1) <= ((((ri)->flags & PNG_INDEXED)-1) & 3))
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typedef const png_transform_control *png_const_transform_controlp;
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typedef const png_row_info *png_const_row_infop;
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#endif /* TRANSFORMS */
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/* Internal functions; these are not exported from a DLL however because they
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* are used within several of the C source files they have to be C extern.
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*
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@@ -1435,6 +1387,64 @@ PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr,
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png_inforp info_ptr),PNG_EMPTY);
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#endif
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#if defined(PNG_READ_TRANSFORMS_SUPPORTED) ||\
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defined(PNG_WRITE_TRANSFORMS_SUPPORTED)
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/***************************** READ and WRITE TRANSFORMS ***********************
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* These structures are used in pngrtran.c, pngwtran.c and pngtrans.c to hold
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* information about transforms in progress. This mechanism was introduced in
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* libpng 1.7.0 to ensure reliable transform code and to fix multiple bugs in
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* the pre-1.7 transform handling.
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*
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* Prior to 1.7.0 the internal transform routines took a png_row_infop, like the
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* user transform function, but without the png_ptr because it was never used.
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* In 1.7.0 a separate internal structure is used in place of this to allow both
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* future development to change the structure.
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*
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* The values in this structure will normally be changed by transformation
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* implementations.
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***************************** READ and WRITE TRANSFORMS **********************/
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typedef struct
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{
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png_const_structrp png_ptr; /* png_struct for error handling and some
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* transform parameters.
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*/
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png_uint_32 width; /* width of row */
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unsigned int channels; /* number of channels (1, 2, 3, or 4) */
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unsigned int bit_depth; /* bit depth of row */
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unsigned int priority; /* priority of the previous transform (see the
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* explanation below for png_transform). */
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# ifdef PNG_READ_GAMMA_SUPPORTED
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png_fixed_point gamma; /* Actual gamma of the row data */
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png_fixed_point gamma_out; /* Expected final gamma after gamma encoding */
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# endif
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unsigned int flags; /* As below */
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# define PNG_INDEXED 1 /* Indexed/palette PNG */
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# define PNG_RGB_SWAPPED 2 /* as in the PNG_BGR transformation */
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# define PNG_FILLER_IN_ALPHA 4 /* 'alpha' channel is really just a filler */
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# define PNG_ALPHA_SWAPPED 8 /* Alpha is in the first channel */
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# define PNG_ALPHA_INVERTED 16 /* Alpha values inverted */
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# define PNG_INVERTED 32 /* grayscale channel inverted */
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# define PNG_BITS_SHIFTED 64 /* Channels not in range 1..(bit_depth-1) */
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# define PNG_BYTE_SWAPPED 128 /* 'swab', i.e. pairs of bytes swapped */
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# define PNG_PIXEL_SWAPPED 256 /* pixels swapped within bytes */
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# define PNG_BAD_INDEX 512 /* Bad palette image index */
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} png_transform_control, *png_transform_controlp;
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/* Validation: channels and bit_depth can be set to anything required by
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* the transform, but the result may not be encodable in PNG. PNG_USURPED
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* must be set in this case. This macro detects the detectably unrepresentable
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* case channels case.
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*
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* Channels: must be 1 when PNG_INDEXED is set, must be 1-4 otherwise, so:
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*
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* (channels-1) <= (((flags & PNG_INDEXED)-1) & 3)
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*/
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#define PNG_VALID_CHANNELS(ri)\
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(((ri)->channels-1) <= ((((ri)->flags & PNG_INDEXED)-1) & 3))
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typedef const png_transform_control *png_const_transform_controlp;
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typedef const png_row_info *png_const_row_infop;
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/* Shared transform functions, defined in pngtran.c */
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#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
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defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
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@@ -1464,6 +1474,7 @@ PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_transform_controlp row_info,
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PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_transform_controlp row_info,
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png_bytep row),PNG_EMPTY);
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#endif
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#endif /* READ_TRANSFORMS || WRITE_TRANSFORMS */
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/* The following decodes the appropriate chunks, and does error correction,
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* then calls the appropriate callback for the chunk if it is valid.
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@@ -2030,15 +2041,6 @@ PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a,
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PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
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PNG_EMPTY);
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#ifdef PNG_READ_GAMMA_SUPPORTED
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/* The same but gives a reciprocal of the product of two fixed point
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* values. Accuracy is suitable for gamma calculations but this is
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* not exact - use png_muldiv for that. Only required at present on read.
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*/
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PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a,
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png_fixed_point b),PNG_EMPTY);
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#endif
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/* Return true if the gamma value is significantly different from 1.0 */
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PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
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PNG_EMPTY);
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@@ -2055,13 +2057,8 @@ PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
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PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_16bit_correct,(
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png_const_structrp png_ptr, png_uint_32 value, png_fixed_point gamma_value),
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PNG_EMPTY);
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PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(
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png_const_structrp png_ptr, png_uint_32 value, png_fixed_point gamma_value),
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PNG_EMPTY);
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PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
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PNG_EMPTY);
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PNG_INTERNAL_FUNCTION(void,png_build_gamma_tables,(png_structrp png_ptr,
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int bit_depth),PNG_EMPTY);
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#endif
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/* SIMPLIFIED READ/WRITE SUPPORT */
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