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Fix decoding of high-color sixel images when the palette changes. #147

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Fix decoding of high-color sixel images when the palette changes. #147

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2 changes: 1 addition & 1 deletion src/decoder.c
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Original file line number Diff line number Diff line change
Expand Up @@ -324,7 +324,7 @@ sixel_decoder_decode(
}

status = sixel_helper_write_image_file(indexed_pixels, sx, sy, palette,
SIXEL_PIXELFORMAT_PAL8,
SIXEL_PIXELFORMAT_RGB888,
decoder->output,
SIXEL_FORMAT_PNG,
decoder->allocator);
Expand Down
61 changes: 34 additions & 27 deletions src/fromsixel.c
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Original file line number Diff line number Diff line change
Expand Up @@ -93,7 +93,6 @@ typedef struct parser_context {
int attributed_pv;
int repeat_count;
int color_index;
int bgindex;
int param;
int nparams;
int params[DECSIXEL_PARAMS_MAX];
Expand Down Expand Up @@ -173,7 +172,6 @@ image_buffer_init(
image_buffer_t *image,
int width,
int height,
int bgindex,
sixel_allocator_t *allocator)
{
SIXELSTATUS status = SIXEL_FALSE;
Expand Down Expand Up @@ -210,7 +208,7 @@ image_buffer_init(
goto end;
}

size = (size_t)(width) * (size_t)height * sizeof(unsigned char);
size = (size_t)(width) * (size_t)height * sizeof(unsigned char) * 3;
image->width = width;
image->height = height;
image->data = (unsigned char *)sixel_allocator_malloc(allocator, size);
Expand All @@ -222,7 +220,8 @@ image_buffer_init(
status = SIXEL_BAD_ALLOCATION;
goto end;
}
memset(image->data, bgindex, size);

memset(image->data, 0, size);

/* palette initialization */
for (n = 0; n < 16; n++) {
Expand All @@ -243,7 +242,7 @@ image_buffer_init(
image->palette[n++] = SIXEL_RGB(i * 11, i * 11, i * 11);
}

for (; n < SIXEL_PALETTE_MAX; n++) {
for (n = 0; n < SIXEL_PALETTE_MAX; n++) {
image->palette[n] = SIXEL_RGB(255, 255, 255);
}

Expand All @@ -259,7 +258,6 @@ image_buffer_resize(
image_buffer_t *image,
int width,
int height,
int bgindex,
sixel_allocator_t *allocator)
{
SIXELSTATUS status = SIXEL_FALSE;
Expand Down Expand Up @@ -300,7 +298,7 @@ image_buffer_resize(
goto end;
}

size = (size_t)width * (size_t)height;
size = 3 * (size_t)width * (size_t)height;
alt_buffer = (unsigned char *)sixel_allocator_malloc(allocator, size);
if (alt_buffer == NULL || size == 0) {
/* free source image */
Expand All @@ -320,24 +318,24 @@ image_buffer_resize(
image->data + (size_t)image->width * (size_t)n,
(size_t)image->width);
/* fill extended area with background color */
memset(alt_buffer + (size_t)width * (size_t)n + (size_t)image->width,
bgindex,
(size_t)(width - image->width));
memset(alt_buffer + ((size_t)width * (size_t)n + (size_t)image->width) * 3,
0,
(size_t)(width - image->width) * 3);
}
} else {
for (n = 0; n < min_height; ++n) {
/* copy from source image */
memcpy(alt_buffer + (size_t)width * (size_t)n,
image->data + (size_t)image->width * (size_t)n,
(size_t)width);
memcpy(alt_buffer + ((size_t)width * (size_t) n) * 3,
image->data + ((size_t)image->width * (size_t) n) * 3,
(size_t) width * 3);
}
}

if (height > image->height) { /* if height is extended */
/* fill extended area with background color */
memset(alt_buffer + (size_t)width * (size_t)image->height,
bgindex,
(size_t)width * (size_t)(height - image->height));
memset(alt_buffer + (size_t)width * (size_t)image->height * 3,
0,
(size_t)width * (size_t)(height - image->height) * 3);
}

/* free source image */
Expand Down Expand Up @@ -370,7 +368,6 @@ parser_context_init(parser_context_t *context)
context->attributed_pv = 0;
context->repeat_count = 1;
context->color_index = 15;
context->bgindex = (-1);
context->nparams = 0;
context->param = 0;

Expand Down Expand Up @@ -603,7 +600,7 @@ sixel_decode_raw_impl(
}

if (sx > image->width || sy > image->height) {
status = image_buffer_resize(image, sx, sy, context->bgindex, allocator);
status = image_buffer_resize(image, sx, sy, allocator);
if (SIXEL_FAILED(status)) {
goto end;
}
Expand All @@ -626,8 +623,12 @@ sixel_decode_raw_impl(
if (context->repeat_count <= 1) {
for (i = 0; i < 6; i++) {
if ((bits & sixel_vertical_mask) != 0) {
pos = (size_t)image->width * (size_t)(context->pos_y + i) + (size_t)context->pos_x;
image->data[pos] = context->color_index;
pos = ((size_t)image->width * (size_t)(context->pos_y + i) + (size_t)context->pos_x) * 3;

image->data[pos + 0] = image->palette[context->color_index] >> 16;
image->data[pos + 1] = image->palette[context->color_index] >> 8;
image->data[pos + 2] = image->palette[context->color_index];

if (context->max_x < context->pos_x) {
context->max_x = context->pos_x;
}
Expand All @@ -650,9 +651,15 @@ sixel_decode_raw_impl(
c <<= 1;
}
for (y = context->pos_y + i; y < context->pos_y + i + n; ++y) {
memset(image->data + (size_t)image->width * (size_t)y + (size_t)context->pos_x,
context->color_index,
(size_t)context->repeat_count);
int j;
pos = ((size_t)image->width * (size_t)y + (size_t)context->pos_x) * 3;

for (j=0; j<context->repeat_count; j++) {
image->data[pos + 0] = image->palette[context->color_index] >> 16;
image->data[pos + 1] = image->palette[context->color_index] >> 8;
image->data[pos + 2] = image->palette[context->color_index];
pos += 3;
}
}
if (context->max_x < (context->pos_x + context->repeat_count - 1)) {
context->max_x = context->pos_x + context->repeat_count - 1;
Expand Down Expand Up @@ -741,7 +748,7 @@ sixel_decode_raw_impl(
sy = image->height;
}

status = image_buffer_resize(image, sx, sy, context->bgindex, allocator);
status = image_buffer_resize(image, sx, sy, allocator);
if (SIXEL_FAILED(status)) {
goto end;
}
Expand Down Expand Up @@ -886,7 +893,7 @@ sixel_decode_raw_impl(
}

if (image->width > context->max_x || image->height > context->max_y) {
status = image_buffer_resize(image, context->max_x, context->max_y, context->bgindex, allocator);
status = image_buffer_resize(image, context->max_x, context->max_y, allocator);
if (SIXEL_FAILED(status)) {
goto end;
}
Expand Down Expand Up @@ -935,7 +942,7 @@ sixel_decode_raw(
}

/* buffer initialization */
status = image_buffer_init(&image, 1, 1, context.bgindex, allocator);
status = image_buffer_init(&image, 1, 1, allocator);
if (SIXEL_FAILED(status)) {
goto error;
}
Expand Down Expand Up @@ -1012,7 +1019,7 @@ sixel_decode(unsigned char /* in */ *p, /* sixel bytes */
}

/* buffer initialization */
status = image_buffer_init(&image, 2048, 2048, context.bgindex, allocator);
status = image_buffer_init(&image, 2048, 2048, allocator);
if (SIXEL_FAILED(status)) {
goto end;
}
Expand Down