ref: 485a3301e6119f0c85d7869d469fc0a0888e49c1
dir: /sys/src/cmd/gs/jpeg/transupp.c/
/*
* transupp.c
*
* Copyright (C) 1997, Thomas G. Lane.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
* This file contains image transformation routines and other utility code
* used by the jpegtran sample application. These are NOT part of the core
* JPEG library. But we keep these routines separate from jpegtran.c to
* ease the task of maintaining jpegtran-like programs that have other user
* interfaces.
*/
/* Although this file really shouldn't have access to the library internals,
* it's helpful to let it call jround_up() and jcopy_block_row().
*/
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
#include "transupp.h" /* My own external interface */
#if TRANSFORMS_SUPPORTED
/*
* Lossless image transformation routines. These routines work on DCT
* coefficient arrays and thus do not require any lossy decompression
* or recompression of the image.
* Thanks to Guido Vollbeding for the initial design and code of this feature.
*
* Horizontal flipping is done in-place, using a single top-to-bottom
* pass through the virtual source array. It will thus be much the
* fastest option for images larger than main memory.
*
* The other routines require a set of destination virtual arrays, so they
* need twice as much memory as jpegtran normally does. The destination
* arrays are always written in normal scan order (top to bottom) because
* the virtual array manager expects this. The source arrays will be scanned
* in the corresponding order, which means multiple passes through the source
* arrays for most of the transforms. That could result in much thrashing
* if the image is larger than main memory.
*
* Some notes about the operating environment of the individual transform
* routines:
* 1. Both the source and destination virtual arrays are allocated from the
* source JPEG object, and therefore should be manipulated by calling the
* source's memory manager.
* 2. The destination's component count should be used. It may be smaller
* than the source's when forcing to grayscale.
* 3. Likewise the destination's sampling factors should be used. When
* forcing to grayscale the destination's sampling factors will be all 1,
* and we may as well take that as the effective iMCU size.
* 4. When "trim" is in effect, the destination's dimensions will be the
* trimmed values but the source's will be untrimmed.
* 5. All the routines assume that the source and destination buffers are
* padded out to a full iMCU boundary. This is true, although for the
* source buffer it is an undocumented property of jdcoefct.c.
* Notes 2,3,4 boil down to this: generally we should use the destination's
* dimensions and ignore the source's.
*/
LOCAL(void)
do_flip_h (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
jvirt_barray_ptr *src_coef_arrays)
/* Horizontal flip; done in-place, so no separate dest array is required */
{
JDIMENSION MCU_cols, comp_width, blk_x, blk_y;
int ci, k, offset_y;
JBLOCKARRAY buffer;
JCOEFPTR ptr1, ptr2;
JCOEF temp1, temp2;
jpeg_component_info *compptr;
/* Horizontal mirroring of DCT blocks is accomplished by swapping
* pairs of blocks in-place. Within a DCT block, we perform horizontal
* mirroring by changing the signs of odd-numbered columns.
* Partial iMCUs at the right edge are left untouched.
*/
MCU_cols = dstinfo->image_width / (dstinfo->max_h_samp_factor * DCTSIZE);
for (ci = 0; ci < dstinfo->num_components; ci++) {
compptr = dstinfo->comp_info + ci;
comp_width = MCU_cols * compptr->h_samp_factor;
for (blk_y = 0; blk_y < compptr->height_in_blocks;
blk_y += compptr->v_samp_factor) {
buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, src_coef_arrays[ci], blk_y,
(JDIMENSION) compptr->v_samp_factor, TRUE);
for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
for (blk_x = 0; blk_x * 2 < comp_width; blk_x++) {
ptr1 = buffer[offset_y][blk_x];
ptr2 = buffer[offset_y][comp_width - blk_x - 1];
/* this unrolled loop doesn't need to know which row it's on... */
for (k = 0; k < DCTSIZE2; k += 2) {
temp1 = *ptr1; /* swap even column */
temp2 = *ptr2;
*ptr1++ = temp2;
*ptr2++ = temp1;
temp1 = *ptr1; /* swap odd column with sign change */
temp2 = *ptr2;
*ptr1++ = -temp2;
*ptr2++ = -temp1;
}
}
}
}
}
}
LOCAL(void)
do_flip_v (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
jvirt_barray_ptr *src_coef_arrays,
jvirt_barray_ptr *dst_coef_arrays)
/* Vertical flip */
{
JDIMENSION MCU_rows, comp_height, dst_blk_x, dst_blk_y;
int ci, i, j, offset_y;
JBLOCKARRAY src_buffer, dst_buffer;
JBLOCKROW src_row_ptr, dst_row_ptr;
JCOEFPTR src_ptr, dst_ptr;
jpeg_component_info *compptr;
/* We output into a separate array because we can't touch different
* rows of the source virtual array simultaneously. Otherwise, this
* is a pretty straightforward analog of horizontal flip.
* Within a DCT block, vertical mirroring is done by changing the signs
* of odd-numbered rows.
* Partial iMCUs at the bottom edge are copied verbatim.
*/
MCU_rows = dstinfo->image_height / (dstinfo->max_v_samp_factor * DCTSIZE);
for (ci = 0; ci < dstinfo->num_components; ci++) {
compptr = dstinfo->comp_info + ci;
comp_height = MCU_rows * compptr->v_samp_factor;
for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
dst_blk_y += compptr->v_samp_factor) {
dst_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
(JDIMENSION) compptr->v_samp_factor, TRUE);
if (dst_blk_y < comp_height) {
/* Row is within the mirrorable area. */
src_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, src_coef_arrays[ci],
comp_height - dst_blk_y - (JDIMENSION) compptr->v_samp_factor,
(JDIMENSION) compptr->v_samp_factor, FALSE);
} else {
/* Bottom-edge blocks will be copied verbatim. */
src_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, src_coef_arrays[ci], dst_blk_y,
(JDIMENSION) compptr->v_samp_factor, FALSE);
}
for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
if (dst_blk_y < comp_height) {
/* Row is within the mirrorable area. */
dst_row_ptr = dst_buffer[offset_y];
src_row_ptr = src_buffer[compptr->v_samp_factor - offset_y - 1];
for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
dst_blk_x++) {
dst_ptr = dst_row_ptr[dst_blk_x];
src_ptr = src_row_ptr[dst_blk_x];
for (i = 0; i < DCTSIZE; i += 2) {
/* copy even row */
for (j = 0; j < DCTSIZE; j++)
*dst_ptr++ = *src_ptr++;
/* copy odd row with sign change */
for (j = 0; j < DCTSIZE; j++)
*dst_ptr++ = - *src_ptr++;
}
}
} else {
/* Just copy row verbatim. */
jcopy_block_row(src_buffer[offset_y], dst_buffer[offset_y],
compptr->width_in_blocks);
}
}
}
}
}
LOCAL(void)
do_transpose (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
jvirt_barray_ptr *src_coef_arrays,
jvirt_barray_ptr *dst_coef_arrays)
/* Transpose source into destination */
{
JDIMENSION dst_blk_x, dst_blk_y;
int ci, i, j, offset_x, offset_y;
JBLOCKARRAY src_buffer, dst_buffer;
JCOEFPTR src_ptr, dst_ptr;
jpeg_component_info *compptr;
/* Transposing pixels within a block just requires transposing the
* DCT coefficients.
* Partial iMCUs at the edges require no special treatment; we simply
* process all the available DCT blocks for every component.
*/
for (ci = 0; ci < dstinfo->num_components; ci++) {
compptr = dstinfo->comp_info + ci;
for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
dst_blk_y += compptr->v_samp_factor) {
dst_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
(JDIMENSION) compptr->v_samp_factor, TRUE);
for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
dst_blk_x += compptr->h_samp_factor) {
src_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, src_coef_arrays[ci], dst_blk_x,
(JDIMENSION) compptr->h_samp_factor, FALSE);
for (offset_x = 0; offset_x < compptr->h_samp_factor; offset_x++) {
src_ptr = src_buffer[offset_x][dst_blk_y + offset_y];
dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
for (i = 0; i < DCTSIZE; i++)
for (j = 0; j < DCTSIZE; j++)
dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
}
}
}
}
}
}
LOCAL(void)
do_rot_90 (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
jvirt_barray_ptr *src_coef_arrays,
jvirt_barray_ptr *dst_coef_arrays)
/* 90 degree rotation is equivalent to
* 1. Transposing the image;
* 2. Horizontal mirroring.
* These two steps are merged into a single processing routine.
*/
{
JDIMENSION MCU_cols, comp_width, dst_blk_x, dst_blk_y;
int ci, i, j, offset_x, offset_y;
JBLOCKARRAY src_buffer, dst_buffer;
JCOEFPTR src_ptr, dst_ptr;
jpeg_component_info *compptr;
/* Because of the horizontal mirror step, we can't process partial iMCUs
* at the (output) right edge properly. They just get transposed and
* not mirrored.
*/
MCU_cols = dstinfo->image_width / (dstinfo->max_h_samp_factor * DCTSIZE);
for (ci = 0; ci < dstinfo->num_components; ci++) {
compptr = dstinfo->comp_info + ci;
comp_width = MCU_cols * compptr->h_samp_factor;
for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
dst_blk_y += compptr->v_samp_factor) {
dst_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
(JDIMENSION) compptr->v_samp_factor, TRUE);
for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
dst_blk_x += compptr->h_samp_factor) {
src_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, src_coef_arrays[ci], dst_blk_x,
(JDIMENSION) compptr->h_samp_factor, FALSE);
for (offset_x = 0; offset_x < compptr->h_samp_factor; offset_x++) {
src_ptr = src_buffer[offset_x][dst_blk_y + offset_y];
if (dst_blk_x < comp_width) {
/* Block is within the mirrorable area. */
dst_ptr = dst_buffer[offset_y]
[comp_width - dst_blk_x - offset_x - 1];
for (i = 0; i < DCTSIZE; i++) {
for (j = 0; j < DCTSIZE; j++)
dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
i++;
for (j = 0; j < DCTSIZE; j++)
dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
}
} else {
/* Edge blocks are transposed but not mirrored. */
dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
for (i = 0; i < DCTSIZE; i++)
for (j = 0; j < DCTSIZE; j++)
dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
}
}
}
}
}
}
}
LOCAL(void)
do_rot_270 (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
jvirt_barray_ptr *src_coef_arrays,
jvirt_barray_ptr *dst_coef_arrays)
/* 270 degree rotation is equivalent to
* 1. Horizontal mirroring;
* 2. Transposing the image.
* These two steps are merged into a single processing routine.
*/
{
JDIMENSION MCU_rows, comp_height, dst_blk_x, dst_blk_y;
int ci, i, j, offset_x, offset_y;
JBLOCKARRAY src_buffer, dst_buffer;
JCOEFPTR src_ptr, dst_ptr;
jpeg_component_info *compptr;
/* Because of the horizontal mirror step, we can't process partial iMCUs
* at the (output) bottom edge properly. They just get transposed and
* not mirrored.
*/
MCU_rows = dstinfo->image_height / (dstinfo->max_v_samp_factor * DCTSIZE);
for (ci = 0; ci < dstinfo->num_components; ci++) {
compptr = dstinfo->comp_info + ci;
comp_height = MCU_rows * compptr->v_samp_factor;
for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
dst_blk_y += compptr->v_samp_factor) {
dst_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
(JDIMENSION) compptr->v_samp_factor, TRUE);
for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
dst_blk_x += compptr->h_samp_factor) {
src_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, src_coef_arrays[ci], dst_blk_x,
(JDIMENSION) compptr->h_samp_factor, FALSE);
for (offset_x = 0; offset_x < compptr->h_samp_factor; offset_x++) {
dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
if (dst_blk_y < comp_height) {
/* Block is within the mirrorable area. */
src_ptr = src_buffer[offset_x]
[comp_height - dst_blk_y - offset_y - 1];
for (i = 0; i < DCTSIZE; i++) {
for (j = 0; j < DCTSIZE; j++) {
dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
j++;
dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
}
}
} else {
/* Edge blocks are transposed but not mirrored. */
src_ptr = src_buffer[offset_x][dst_blk_y + offset_y];
for (i = 0; i < DCTSIZE; i++)
for (j = 0; j < DCTSIZE; j++)
dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
}
}
}
}
}
}
}
LOCAL(void)
do_rot_180 (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
jvirt_barray_ptr *src_coef_arrays,
jvirt_barray_ptr *dst_coef_arrays)
/* 180 degree rotation is equivalent to
* 1. Vertical mirroring;
* 2. Horizontal mirroring.
* These two steps are merged into a single processing routine.
*/
{
JDIMENSION MCU_cols, MCU_rows, comp_width, comp_height, dst_blk_x, dst_blk_y;
int ci, i, j, offset_y;
JBLOCKARRAY src_buffer, dst_buffer;
JBLOCKROW src_row_ptr, dst_row_ptr;
JCOEFPTR src_ptr, dst_ptr;
jpeg_component_info *compptr;
MCU_cols = dstinfo->image_width / (dstinfo->max_h_samp_factor * DCTSIZE);
MCU_rows = dstinfo->image_height / (dstinfo->max_v_samp_factor * DCTSIZE);
for (ci = 0; ci < dstinfo->num_components; ci++) {
compptr = dstinfo->comp_info + ci;
comp_width = MCU_cols * compptr->h_samp_factor;
comp_height = MCU_rows * compptr->v_samp_factor;
for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
dst_blk_y += compptr->v_samp_factor) {
dst_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
(JDIMENSION) compptr->v_samp_factor, TRUE);
if (dst_blk_y < comp_height) {
/* Row is within the vertically mirrorable area. */
src_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, src_coef_arrays[ci],
comp_height - dst_blk_y - (JDIMENSION) compptr->v_samp_factor,
(JDIMENSION) compptr->v_samp_factor, FALSE);
} else {
/* Bottom-edge rows are only mirrored horizontally. */
src_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, src_coef_arrays[ci], dst_blk_y,
(JDIMENSION) compptr->v_samp_factor, FALSE);
}
for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
if (dst_blk_y < comp_height) {
/* Row is within the mirrorable area. */
dst_row_ptr = dst_buffer[offset_y];
src_row_ptr = src_buffer[compptr->v_samp_factor - offset_y - 1];
/* Process the blocks that can be mirrored both ways. */
for (dst_blk_x = 0; dst_blk_x < comp_width; dst_blk_x++) {
dst_ptr = dst_row_ptr[dst_blk_x];
src_ptr = src_row_ptr[comp_width - dst_blk_x - 1];
for (i = 0; i < DCTSIZE; i += 2) {
/* For even row, negate every odd column. */
for (j = 0; j < DCTSIZE; j += 2) {
*dst_ptr++ = *src_ptr++;
*dst_ptr++ = - *src_ptr++;
}
/* For odd row, negate every even column. */
for (j = 0; j < DCTSIZE; j += 2) {
*dst_ptr++ = - *src_ptr++;
*dst_ptr++ = *src_ptr++;
}
}
}
/* Any remaining right-edge blocks are only mirrored vertically. */
for (; dst_blk_x < compptr->width_in_blocks; dst_blk_x++) {
dst_ptr = dst_row_ptr[dst_blk_x];
src_ptr = src_row_ptr[dst_blk_x];
for (i = 0; i < DCTSIZE; i += 2) {
for (j = 0; j < DCTSIZE; j++)
*dst_ptr++ = *src_ptr++;
for (j = 0; j < DCTSIZE; j++)
*dst_ptr++ = - *src_ptr++;
}
}
} else {
/* Remaining rows are just mirrored horizontally. */
dst_row_ptr = dst_buffer[offset_y];
src_row_ptr = src_buffer[offset_y];
/* Process the blocks that can be mirrored. */
for (dst_blk_x = 0; dst_blk_x < comp_width; dst_blk_x++) {
dst_ptr = dst_row_ptr[dst_blk_x];
src_ptr = src_row_ptr[comp_width - dst_blk_x - 1];
for (i = 0; i < DCTSIZE2; i += 2) {
*dst_ptr++ = *src_ptr++;
*dst_ptr++ = - *src_ptr++;
}
}
/* Any remaining right-edge blocks are only copied. */
for (; dst_blk_x < compptr->width_in_blocks; dst_blk_x++) {
dst_ptr = dst_row_ptr[dst_blk_x];
src_ptr = src_row_ptr[dst_blk_x];
for (i = 0; i < DCTSIZE2; i++)
*dst_ptr++ = *src_ptr++;
}
}
}
}
}
}
LOCAL(void)
do_transverse (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
jvirt_barray_ptr *src_coef_arrays,
jvirt_barray_ptr *dst_coef_arrays)
/* Transverse transpose is equivalent to
* 1. 180 degree rotation;
* 2. Transposition;
* or
* 1. Horizontal mirroring;
* 2. Transposition;
* 3. Horizontal mirroring.
* These steps are merged into a single processing routine.
*/
{
JDIMENSION MCU_cols, MCU_rows, comp_width, comp_height, dst_blk_x, dst_blk_y;
int ci, i, j, offset_x, offset_y;
JBLOCKARRAY src_buffer, dst_buffer;
JCOEFPTR src_ptr, dst_ptr;
jpeg_component_info *compptr;
MCU_cols = dstinfo->image_width / (dstinfo->max_h_samp_factor * DCTSIZE);
MCU_rows = dstinfo->image_height / (dstinfo->max_v_samp_factor * DCTSIZE);
for (ci = 0; ci < dstinfo->num_components; ci++) {
compptr = dstinfo->comp_info + ci;
comp_width = MCU_cols * compptr->h_samp_factor;
comp_height = MCU_rows * compptr->v_samp_factor;
for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
dst_blk_y += compptr->v_samp_factor) {
dst_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
(JDIMENSION) compptr->v_samp_factor, TRUE);
for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
dst_blk_x += compptr->h_samp_factor) {
src_buffer = (*srcinfo->mem->access_virt_barray)
((j_common_ptr) srcinfo, src_coef_arrays[ci], dst_blk_x,
(JDIMENSION) compptr->h_samp_factor, FALSE);
for (offset_x = 0; offset_x < compptr->h_samp_factor; offset_x++) {
if (dst_blk_y < comp_height) {
src_ptr = src_buffer[offset_x]
[comp_height - dst_blk_y - offset_y - 1];
if (dst_blk_x < comp_width) {
/* Block is within the mirrorable area. */
dst_ptr = dst_buffer[offset_y]
[comp_width - dst_blk_x - offset_x - 1];
for (i = 0; i < DCTSIZE; i++) {
for (j = 0; j < DCTSIZE; j++) {
dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
j++;
dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
}
i++;
for (j = 0; j < DCTSIZE; j++) {
dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
j++;
dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
}
}
} else {
/* Right-edge blocks are mirrored in y only */
dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
for (i = 0; i < DCTSIZE; i++) {
for (j = 0; j < DCTSIZE; j++) {
dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
j++;
dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
}
}
}
} else {
src_ptr = src_buffer[offset_x][dst_blk_y + offset_y];
if (dst_blk_x < comp_width) {
/* Bottom-edge blocks are mirrored in x only */
dst_ptr = dst_buffer[offset_y]
[comp_width - dst_blk_x - offset_x - 1];
for (i = 0; i < DCTSIZE; i++) {
for (j = 0; j < DCTSIZE; j++)
dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
i++;
for (j = 0; j < DCTSIZE; j++)
dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
}
} else {
/* At lower right corner, just transpose, no mirroring */
dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
for (i = 0; i < DCTSIZE; i++)
for (j = 0; j < DCTSIZE; j++)
dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
}
}
}
}
}
}
}
}
/* Request any required workspace.
*
* We allocate the workspace virtual arrays from the source decompression
* object, so that all the arrays (both the original data and the workspace)
* will be taken into account while making memory management decisions.
* Hence, this routine must be called after jpeg_read_header (which reads
* the image dimensions) and before jpeg_read_coefficients (which realizes
* the source's virtual arrays).
*/
GLOBAL(void)
jtransform_request_workspace (j_decompress_ptr srcinfo,
jpeg_transform_info *info)
{
jvirt_barray_ptr *coef_arrays = NULL;
jpeg_component_info *compptr;
int ci;
if (info->force_grayscale &&
srcinfo->jpeg_color_space == JCS_YCbCr &&
srcinfo->num_components == 3) {
/* We'll only process the first component */
info->num_components = 1;
} else {
/* Process all the components */
info->num_components = srcinfo->num_components;
}
switch (info->transform) {
case JXFORM_NONE:
case JXFORM_FLIP_H:
/* Don't need a workspace array */
break;
case JXFORM_FLIP_V:
case JXFORM_ROT_180:
/* Need workspace arrays having same dimensions as source image.
* Note that we allocate arrays padded out to the next iMCU boundary,
* so that transform routines need not worry about missing edge blocks.
*/
coef_arrays = (jvirt_barray_ptr *)
(*srcinfo->mem->alloc_small) ((j_common_ptr) srcinfo, JPOOL_IMAGE,
SIZEOF(jvirt_barray_ptr) * info->num_components);
for (ci = 0; ci < info->num_components; ci++) {
compptr = srcinfo->comp_info + ci;
coef_arrays[ci] = (*srcinfo->mem->request_virt_barray)
((j_common_ptr) srcinfo, JPOOL_IMAGE, FALSE,
(JDIMENSION) jround_up((long) compptr->width_in_blocks,
(long) compptr->h_samp_factor),
(JDIMENSION) jround_up((long) compptr->height_in_blocks,
(long) compptr->v_samp_factor),
(JDIMENSION) compptr->v_samp_factor);
}
break;
case JXFORM_TRANSPOSE:
case JXFORM_TRANSVERSE:
case JXFORM_ROT_90:
case JXFORM_ROT_270:
/* Need workspace arrays having transposed dimensions.
* Note that we allocate arrays padded out to the next iMCU boundary,
* so that transform routines need not worry about missing edge blocks.
*/
coef_arrays = (jvirt_barray_ptr *)
(*srcinfo->mem->alloc_small) ((j_common_ptr) srcinfo, JPOOL_IMAGE,
SIZEOF(jvirt_barray_ptr) * info->num_components);
for (ci = 0; ci < info->num_components; ci++) {
compptr = srcinfo->comp_info + ci;
coef_arrays[ci] = (*srcinfo->mem->request_virt_barray)
((j_common_ptr) srcinfo, JPOOL_IMAGE, FALSE,
(JDIMENSION) jround_up((long) compptr->height_in_blocks,
(long) compptr->v_samp_factor),
(JDIMENSION) jround_up((long) compptr->width_in_blocks,
(long) compptr->h_samp_factor),
(JDIMENSION) compptr->h_samp_factor);
}
break;
}
info->workspace_coef_arrays = coef_arrays;
}
/* Transpose destination image parameters */
LOCAL(void)
transpose_critical_parameters (j_compress_ptr dstinfo)
{
int tblno, i, j, ci, itemp;
jpeg_component_info *compptr;
JQUANT_TBL *qtblptr;
JDIMENSION dtemp;
UINT16 qtemp;
/* Transpose basic image dimensions */
dtemp = dstinfo->image_width;
dstinfo->image_width = dstinfo->image_height;
dstinfo->image_height = dtemp;
/* Transpose sampling factors */
for (ci = 0; ci < dstinfo->num_components; ci++) {
compptr = dstinfo->comp_info + ci;
itemp = compptr->h_samp_factor;
compptr->h_samp_factor = compptr->v_samp_factor;
compptr->v_samp_factor = itemp;
}
/* Transpose quantization tables */
for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
qtblptr = dstinfo->quant_tbl_ptrs[tblno];
if (qtblptr != NULL) {
for (i = 0; i < DCTSIZE; i++) {
for (j = 0; j < i; j++) {
qtemp = qtblptr->quantval[i*DCTSIZE+j];
qtblptr->quantval[i*DCTSIZE+j] = qtblptr->quantval[j*DCTSIZE+i];
qtblptr->quantval[j*DCTSIZE+i] = qtemp;
}
}
}
}
}
/* Trim off any partial iMCUs on the indicated destination edge */
LOCAL(void)
trim_right_edge (j_compress_ptr dstinfo)
{
int ci, max_h_samp_factor;
JDIMENSION MCU_cols;
/* We have to compute max_h_samp_factor ourselves,
* because it hasn't been set yet in the destination
* (and we don't want to use the source's value).
*/
max_h_samp_factor = 1;
for (ci = 0; ci < dstinfo->num_components; ci++) {
int h_samp_factor = dstinfo->comp_info[ci].h_samp_factor;
max_h_samp_factor = MAX(max_h_samp_factor, h_samp_factor);
}
MCU_cols = dstinfo->image_width / (max_h_samp_factor * DCTSIZE);
if (MCU_cols > 0) /* can't trim to 0 pixels */
dstinfo->image_width = MCU_cols * (max_h_samp_factor * DCTSIZE);
}
LOCAL(void)
trim_bottom_edge (j_compress_ptr dstinfo)
{
int ci, max_v_samp_factor;
JDIMENSION MCU_rows;
/* We have to compute max_v_samp_factor ourselves,
* because it hasn't been set yet in the destination
* (and we don't want to use the source's value).
*/
max_v_samp_factor = 1;
for (ci = 0; ci < dstinfo->num_components; ci++) {
int v_samp_factor = dstinfo->comp_info[ci].v_samp_factor;
max_v_samp_factor = MAX(max_v_samp_factor, v_samp_factor);
}
MCU_rows = dstinfo->image_height / (max_v_samp_factor * DCTSIZE);
if (MCU_rows > 0) /* can't trim to 0 pixels */
dstinfo->image_height = MCU_rows * (max_v_samp_factor * DCTSIZE);
}
/* Adjust output image parameters as needed.
*
* This must be called after jpeg_copy_critical_parameters()
* and before jpeg_write_coefficients().
*
* The return value is the set of virtual coefficient arrays to be written
* (either the ones allocated by jtransform_request_workspace, or the
* original source data arrays). The caller will need to pass this value
* to jpeg_write_coefficients().
*/
GLOBAL(jvirt_barray_ptr *)
jtransform_adjust_parameters (j_decompress_ptr srcinfo,
j_compress_ptr dstinfo,
jvirt_barray_ptr *src_coef_arrays,
jpeg_transform_info *info)
{
/* If force-to-grayscale is requested, adjust destination parameters */
if (info->force_grayscale) {
/* We use jpeg_set_colorspace to make sure subsidiary settings get fixed
* properly. Among other things, the target h_samp_factor & v_samp_factor
* will get set to 1, which typically won't match the source.
* In fact we do this even if the source is already grayscale; that
* provides an easy way of coercing a grayscale JPEG with funny sampling
* factors to the customary 1,1. (Some decoders fail on other factors.)
*/
if ((dstinfo->jpeg_color_space == JCS_YCbCr &&
dstinfo->num_components == 3) ||
(dstinfo->jpeg_color_space == JCS_GRAYSCALE &&
dstinfo->num_components == 1)) {
/* We have to preserve the source's quantization table number. */
int sv_quant_tbl_no = dstinfo->comp_info[0].quant_tbl_no;
jpeg_set_colorspace(dstinfo, JCS_GRAYSCALE);
dstinfo->comp_info[0].quant_tbl_no = sv_quant_tbl_no;
} else {
/* Sorry, can't do it */
ERREXIT(dstinfo, JERR_CONVERSION_NOTIMPL);
}
}
/* Correct the destination's image dimensions etc if necessary */
switch (info->transform) {
case JXFORM_NONE:
/* Nothing to do */
break;
case JXFORM_FLIP_H:
if (info->trim)
trim_right_edge(dstinfo);
break;
case JXFORM_FLIP_V:
if (info->trim)
trim_bottom_edge(dstinfo);
break;
case JXFORM_TRANSPOSE:
transpose_critical_parameters(dstinfo);
/* transpose does NOT have to trim anything */
break;
case JXFORM_TRANSVERSE:
transpose_critical_parameters(dstinfo);
if (info->trim) {
trim_right_edge(dstinfo);
trim_bottom_edge(dstinfo);
}
break;
case JXFORM_ROT_90:
transpose_critical_parameters(dstinfo);
if (info->trim)
trim_right_edge(dstinfo);
break;
case JXFORM_ROT_180:
if (info->trim) {
trim_right_edge(dstinfo);
trim_bottom_edge(dstinfo);
}
break;
case JXFORM_ROT_270:
transpose_critical_parameters(dstinfo);
if (info->trim)
trim_bottom_edge(dstinfo);
break;
}
/* Return the appropriate output data set */
if (info->workspace_coef_arrays != NULL)
return info->workspace_coef_arrays;
return src_coef_arrays;
}
/* Execute the actual transformation, if any.
*
* This must be called *after* jpeg_write_coefficients, because it depends
* on jpeg_write_coefficients to have computed subsidiary values such as
* the per-component width and height fields in the destination object.
*
* Note that some transformations will modify the source data arrays!
*/
GLOBAL(void)
jtransform_execute_transformation (j_decompress_ptr srcinfo,
j_compress_ptr dstinfo,
jvirt_barray_ptr *src_coef_arrays,
jpeg_transform_info *info)
{
jvirt_barray_ptr *dst_coef_arrays = info->workspace_coef_arrays;
switch (info->transform) {
case JXFORM_NONE:
break;
case JXFORM_FLIP_H:
do_flip_h(srcinfo, dstinfo, src_coef_arrays);
break;
case JXFORM_FLIP_V:
do_flip_v(srcinfo, dstinfo, src_coef_arrays, dst_coef_arrays);
break;
case JXFORM_TRANSPOSE:
do_transpose(srcinfo, dstinfo, src_coef_arrays, dst_coef_arrays);
break;
case JXFORM_TRANSVERSE:
do_transverse(srcinfo, dstinfo, src_coef_arrays, dst_coef_arrays);
break;
case JXFORM_ROT_90:
do_rot_90(srcinfo, dstinfo, src_coef_arrays, dst_coef_arrays);
break;
case JXFORM_ROT_180:
do_rot_180(srcinfo, dstinfo, src_coef_arrays, dst_coef_arrays);
break;
case JXFORM_ROT_270:
do_rot_270(srcinfo, dstinfo, src_coef_arrays, dst_coef_arrays);
break;
}
}
#endif /* TRANSFORMS_SUPPORTED */
/* Setup decompression object to save desired markers in memory.
* This must be called before jpeg_read_header() to have the desired effect.
*/
GLOBAL(void)
jcopy_markers_setup (j_decompress_ptr srcinfo, JCOPY_OPTION option)
{
#ifdef SAVE_MARKERS_SUPPORTED
int m;
/* Save comments except under NONE option */
if (option != JCOPYOPT_NONE) {
jpeg_save_markers(srcinfo, JPEG_COM, 0xFFFF);
}
/* Save all types of APPn markers iff ALL option */
if (option == JCOPYOPT_ALL) {
for (m = 0; m < 16; m++)
jpeg_save_markers(srcinfo, JPEG_APP0 + m, 0xFFFF);
}
#endif /* SAVE_MARKERS_SUPPORTED */
}
/* Copy markers saved in the given source object to the destination object.
* This should be called just after jpeg_start_compress() or
* jpeg_write_coefficients().
* Note that those routines will have written the SOI, and also the
* JFIF APP0 or Adobe APP14 markers if selected.
*/
GLOBAL(void)
jcopy_markers_execute (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
JCOPY_OPTION option)
{
jpeg_saved_marker_ptr marker;
/* In the current implementation, we don't actually need to examine the
* option flag here; we just copy everything that got saved.
* But to avoid confusion, we do not output JFIF and Adobe APP14 markers
* if the encoder library already wrote one.
*/
for (marker = srcinfo->marker_list; marker != NULL; marker = marker->next) {
if (dstinfo->write_JFIF_header &&
marker->marker == JPEG_APP0 &&
marker->data_length >= 5 &&
GETJOCTET(marker->data[0]) == 0x4A &&
GETJOCTET(marker->data[1]) == 0x46 &&
GETJOCTET(marker->data[2]) == 0x49 &&
GETJOCTET(marker->data[3]) == 0x46 &&
GETJOCTET(marker->data[4]) == 0)
continue; /* reject duplicate JFIF */
if (dstinfo->write_Adobe_marker &&
marker->marker == JPEG_APP0+14 &&
marker->data_length >= 5 &&
GETJOCTET(marker->data[0]) == 0x41 &&
GETJOCTET(marker->data[1]) == 0x64 &&
GETJOCTET(marker->data[2]) == 0x6F &&
GETJOCTET(marker->data[3]) == 0x62 &&
GETJOCTET(marker->data[4]) == 0x65)
continue; /* reject duplicate Adobe */
#ifdef NEED_FAR_POINTERS
/* We could use jpeg_write_marker if the data weren't FAR... */
{
unsigned int i;
jpeg_write_m_header(dstinfo, marker->marker, marker->data_length);
for (i = 0; i < marker->data_length; i++)
jpeg_write_m_byte(dstinfo, marker->data[i]);
}
#else
jpeg_write_marker(dstinfo, marker->marker,
marker->data, marker->data_length);
#endif
}
}