cleanup WebPPicture struct and API

* add a real proper pointer for holding memory chunk pointer
  (instead of using y and argb fields)
* polish the doc with details
* add a WebPPictureView() that extract a view from a picture
  without any copy (kind of a fast-crop).
* properly snap the top-left corner for Crop/View. Previously,
  the luma position was not snapped, and was off compared to the chroma.

Change-Id: I8a3620c7f5fc6f7d1f8dd89d9da167c91e237439
This commit is contained in:
Pascal Massimino 2012-06-21 00:30:43 -07:00
parent 9144a18643
commit 31b68fe639
3 changed files with 145 additions and 39 deletions

View File

@ -1023,9 +1023,12 @@ int main(int argc, const char *argv[]) {
if (verbose) {
StopwatchReadAndReset(&stop_watch);
}
if (crop != 0 && !WebPPictureCrop(&picture, crop_x, crop_y, crop_w, crop_h)) {
fprintf(stderr, "Error! Cannot crop picture\n");
goto Error;
if (crop != 0) {
// We use self-cropping using a view.
if (!WebPPictureView(&picture, crop_x, crop_y, crop_w, crop_h, &picture)) {
fprintf(stderr, "Error! Cannot crop picture\n");
goto Error;
}
}
if ((resize_w | resize_h) > 0) {
if (!WebPPictureRescale(&picture, resize_w, resize_h)) {

View File

@ -21,6 +21,7 @@ extern "C" {
#endif
#define HALVE(x) (((x) + 1) >> 1)
#define IS_YUV_CSP(csp, YUV_CSP) (((csp) & WEBP_CSP_UV_MASK) == (YUV_CSP))
//------------------------------------------------------------------------------
// WebPPicture
@ -86,6 +87,9 @@ int WebPPictureAlloc(WebPPicture* const picture) {
mem = (uint8_t*)malloc((size_t)total_size);
if (mem == NULL) return 0;
picture->memory_ = (void*)mem;
// TODO(skal): we could align the y/u/v planes and adjust stride.
picture->y = mem;
mem += y_size;
@ -105,6 +109,7 @@ int WebPPictureAlloc(WebPPicture* const picture) {
mem += uv0_size;
}
} else {
void* memory;
const uint64_t argb_size = (uint64_t)width * height;
const uint64_t total_size = argb_size * sizeof(*picture->argb);
if (width <= 0 || height <= 0 ||
@ -113,8 +118,12 @@ int WebPPictureAlloc(WebPPicture* const picture) {
return 0;
}
WebPPictureFree(picture); // erase previous buffer
picture->argb = (uint32_t*)malloc((size_t)total_size);
if (picture->argb == NULL) return 0;
memory = malloc((size_t)total_size);
if (memory == NULL) return 0;
picture->memory_argb_ = memory;
// TODO(skal): align plane to cache line?
picture->argb = (uint32_t*)memory;
picture->argb_stride = width;
}
}
@ -125,18 +134,21 @@ int WebPPictureAlloc(WebPPicture* const picture) {
// into 'dst'. Mark 'dst' as not owning any memory. 'src' can be NULL.
static void WebPPictureGrabSpecs(const WebPPicture* const src,
WebPPicture* const dst) {
assert(dst != NULL);
if (src != NULL) *dst = *src;
dst->y = dst->u = dst->v = NULL;
dst->u0 = dst->v0 = NULL;
dst->a = NULL;
dst->argb = NULL;
dst->memory_ = NULL;
dst->memory_argb_ = NULL;
}
// Release memory owned by 'picture'.
void WebPPictureFree(WebPPicture* const picture) {
if (picture != NULL) {
free(picture->y);
free(picture->argb);
free(picture->memory_);
free(picture->memory_argb_);
WebPPictureGrabSpecs(NULL, picture);
}
}
@ -154,6 +166,30 @@ static void CopyPlane(const uint8_t* src, int src_stride,
}
}
// Adjust top-left corner to chroma sample position.
static void SnapTopLeftPosition(const WebPPicture* const pic,
int* const left, int* const top) {
if (!pic->use_argb_input) {
const int is_yuv422 = IS_YUV_CSP(pic->colorspace, WEBP_YUV422);
if (IS_YUV_CSP(pic->colorspace, WEBP_YUV420) || is_yuv422) {
*left &= ~1;
if (!is_yuv422) *top &= ~1;
}
}
}
// Adjust top-left corner and verify that the sub-rectangle is valid.
static int AdjustAndCheckRectangle(const WebPPicture* const pic,
int* const left, int* const top,
int width, int height) {
SnapTopLeftPosition(pic, left, top);
if ((*left) < 0 || (*top) < 0) return 0;
if (width <= 0 || height <= 0) return 0;
if ((*left) + width > pic->width) return 0;
if ((*top) + height > pic->height) return 0;
return 1;
}
int WebPPictureCopy(const WebPPicture* const src, WebPPicture* const dst) {
if (src == NULL || dst == NULL) return 0;
if (src == dst) return 1;
@ -175,7 +211,7 @@ int WebPPictureCopy(const WebPPicture* const src, WebPPicture* const dst) {
#ifdef WEBP_EXPERIMENTAL_FEATURES
if (dst->u0 != NULL) {
int uv0_width = src->width;
if ((dst->colorspace & WEBP_CSP_UV_MASK) == WEBP_YUV422) {
if (IS_YUV_CSP(dst->colorspace, WEBP_YUV422)) {
uv0_width = HALVE(uv0_width);
}
CopyPlane(src->u0, src->uv0_stride,
@ -192,6 +228,48 @@ int WebPPictureCopy(const WebPPicture* const src, WebPPicture* const dst) {
return 1;
}
int WebPPictureIsView(const WebPPicture* const picture) {
if (picture == NULL) return 0;
if (picture->use_argb_input) {
return (picture->memory_argb_ == NULL);
}
return (picture->memory_ == NULL);
}
int WebPPictureView(const WebPPicture* const src,
int left, int top, int width, int height,
WebPPicture* const dst) {
if (src == NULL || dst == NULL) return 0;
// verify rectangle position.
if (!AdjustAndCheckRectangle(src, &left, &top, width, height)) return 0;
if (src != dst) { // beware of aliasing! We don't want to leak 'memory_'.
WebPPictureGrabSpecs(src, dst);
}
dst->width = width;
dst->height = height;
if (!src->use_argb_input) {
dst->y = src->y + top * src->y_stride + left;
dst->u = src->u + (top >> 1) * src->uv_stride + (left >> 1);
dst->v = src->v + (top >> 1) * src->uv_stride + (left >> 1);
if (src->a != NULL) {
dst->a = src->a + top * src->a_stride + left;
}
#ifdef WEBP_EXPERIMENTAL_FEATURES
if (src->u0 != NULL) {
const int left_pos =
IS_YUV_CSP(dst->colorspace, WEBP_YUV422) ? (left >> 1) : left;
dst->u0 = src->u0 + top * src->uv0_stride + left_pos;
dst->v0 = src->v0 + top * src->uv0_stride + left_pos;
}
#endif
} else {
dst->argb = src->argb + top * src->argb_stride + left;
}
return 1;
}
//------------------------------------------------------------------------------
// Picture cropping
@ -200,9 +278,7 @@ int WebPPictureCrop(WebPPicture* const pic,
WebPPicture tmp;
if (pic == NULL) return 0;
if (width <= 0 || height <= 0) return 0;
if (left < 0 || ((left + width + 1) & ~1) > pic->width) return 0;
if (top < 0 || ((top + height + 1) & ~1) > pic->height) return 0;
if (!AdjustAndCheckRectangle(pic, &left, &top, width, height)) return 0;
WebPPictureGrabSpecs(pic, &tmp);
tmp.width = width;
@ -227,15 +303,15 @@ int WebPPictureCrop(WebPPicture* const pic,
#ifdef WEBP_EXPERIMENTAL_FEATURES
if (tmp.u0 != NULL) {
int w = width;
int l = left;
if (tmp.colorspace == WEBP_YUV422) {
int left_pos = left;
if (IS_YUV_CSP(tmp.colorspace, WEBP_YUV422)) {
w = HALVE(w);
l = HALVE(l);
left_pos = HALVE(left_pos);
}
CopyPlane(pic->u0 + top * pic->uv0_stride + l, pic->uv0_stride,
tmp.u0, tmp.uv0_stride, w, l);
CopyPlane(pic->v0 + top * pic->uv0_stride + l, pic->uv0_stride,
tmp.v0, tmp.uv0_stride, w, l);
CopyPlane(pic->u0 + top * pic->uv0_stride + left_pos, pic->uv0_stride,
tmp.u0, tmp.uv0_stride, w, height);
CopyPlane(pic->v0 + top * pic->uv0_stride + left_pos, pic->uv0_stride,
tmp.v0, tmp.uv0_stride, w, height);
}
#endif
} else {
@ -323,10 +399,7 @@ int WebPPictureRescale(WebPPicture* const pic, int width, int height) {
}
#ifdef WEBP_EXPERIMENTAL_FEATURES
if (tmp.u0 != NULL) {
int s = 1;
if ((tmp.colorspace & WEBP_CSP_UV_MASK) == WEBP_YUV422) {
s = 2;
}
const int s = IS_YUV_CSP(tmp.colorspace, WEBP_YUV422) ? 2 : 1;
RescalePlane(
pic->u0, (prev_width + s / 2) / s, prev_height, pic->uv0_stride,
tmp.u0, (width + s / 2) / s, height, tmp.uv0_stride, work, 1);

View File

@ -95,8 +95,8 @@ WEBP_EXTERN(int) WebPConfigInitInternal(
WebPConfig* const, WebPPreset, float, int);
// Should always be called, to initialize a fresh WebPConfig structure before
// modification. Returns 0 in case of version mismatch. WebPConfigInit() must
// have succeeded before using the 'config' object.
// modification. Returns false in case of version mismatch. WebPConfigInit()
// must have succeeded before using the 'config' object.
static WEBP_INLINE int WebPConfigInit(WebPConfig* const config) {
return WebPConfigInitInternal(config, WEBP_PRESET_DEFAULT, 75.f,
WEBP_ENCODER_ABI_VERSION);
@ -105,14 +105,15 @@ static WEBP_INLINE int WebPConfigInit(WebPConfig* const config) {
// This function will initialize the configuration according to a predefined
// set of parameters (referred to by 'preset') and a given quality factor.
// This function can be called as a replacement to WebPConfigInit(). Will
// return 0 in case of error.
// return false in case of error.
static WEBP_INLINE int WebPConfigPreset(WebPConfig* const config,
WebPPreset preset, float quality) {
return WebPConfigInitInternal(config, preset, quality,
WEBP_ENCODER_ABI_VERSION);
}
// Returns 1 if all parameters are in valid range and the configuration is OK.
// Returns true if 'config' is non-NULL and all configuration parameters are
// within their valid ranges.
WEBP_EXTERN(int) WebPValidateConfig(const WebPConfig* const config);
//------------------------------------------------------------------------------
@ -140,7 +141,7 @@ typedef struct {
// used during callbacks (like progress-report e.g.).
} WebPAuxStats;
// Signature for output function. Should return 1 if writing was successful.
// Signature for output function. Should return true if writing was successful.
// data/data_size is the segment of data to write, and 'picture' is for
// reference (and so one can make use of picture->custom_ptr).
typedef int (*WebPWriterFunction)(const uint8_t* data, size_t data_size,
@ -162,8 +163,9 @@ WEBP_EXTERN(void) WebPMemoryWriterInit(WebPMemoryWriter* const writer);
WEBP_EXTERN(int) WebPMemoryWrite(const uint8_t* data, size_t data_size,
const WebPPicture* const picture);
// Progress hook, called from time to time to report progress. It can return 0
// to request an abort of the encoding process, or 1 otherwise if all is OK.
// Progress hook, called from time to time to report progress. It can return
// false to request an abort of the encoding process, or true otherwise if
// everything is OK.
typedef int (*WebPProgressHook)(int percent, const WebPPicture* const picture);
typedef enum {
@ -237,13 +239,17 @@ struct WebPPicture {
int use_argb_input; // Flag for encoder to use argb pixels as input.
uint32_t* argb; // Pointer to argb (32 bit) plane.
int argb_stride; // This is stride in pixels units, not bytes.
// private fields:
void* memory_; // row chunk of memory for yuva planes
void* memory_argb_; // and for argb too.
};
// Internal, version-checked, entry point
WEBP_EXTERN(int) WebPPictureInitInternal(WebPPicture* const, int);
// Should always be called, to initialize the structure. Returns 0 in case of
// version mismatch. WebPPictureInit() must have succeeded before using the
// Should always be called, to initialize the structure. Returns false in case
// of version mismatch. WebPPictureInit() must have succeeded before using the
// 'picture' object.
static WEBP_INLINE int WebPPictureInit(WebPPicture* const picture) {
return WebPPictureInitInternal(picture, WEBP_ENCODER_ABI_VERSION);
@ -255,21 +261,23 @@ static WEBP_INLINE int WebPPictureInit(WebPPicture* const picture) {
// Convenience allocation / deallocation based on picture->width/height:
// Allocate y/u/v buffers as per colorspace/width/height specification.
// Note! This function will free the previous buffer if needed.
// Returns 0 in case of memory error.
// Returns false in case of memory error.
WEBP_EXTERN(int) WebPPictureAlloc(WebPPicture* const picture);
// Release memory allocated by WebPPictureAlloc() or WebPPictureImport*()
// Note that this function does _not_ free the memory pointed to by 'picture'.
// Release the memory allocated by WebPPictureAlloc() or WebPPictureImport*().
// Note that this function does _not_ free the memory used by the 'picture'
// object itself.
WEBP_EXTERN(void) WebPPictureFree(WebPPicture* const picture);
// Copy the pixels of *src into *dst, using WebPPictureAlloc.
// Returns 0 in case of memory allocation error.
// Copy the pixels of *src into *dst, using WebPPictureAlloc. Upon return,
// *dst will fully own the copied pixels (this is not a view).
// Returns false in case of memory allocation error.
WEBP_EXTERN(int) WebPPictureCopy(const WebPPicture* const src,
WebPPicture* const dst);
// Compute PSNR or SSIM distortion between two pictures.
// Result is in dB, stores in result[] in the Y/U/V/Alpha/All order.
// Returns 0 in case of error (pic1 and pic2 don't have same dimension, ...)
// Returns false in case of error (pic1 and pic2 don't have same dimension, ...)
// Warning: this function is rather CPU-intensive.
WEBP_EXTERN(int) WebPPictureDistortion(
const WebPPicture* const pic1, const WebPPicture* const pic2,
@ -277,11 +285,33 @@ WEBP_EXTERN(int) WebPPictureDistortion(
float result[5]);
// self-crops a picture to the rectangle defined by top/left/width/height.
// Returns 0 in case of memory allocation error, or if the rectangle is
// Returns false in case of memory allocation error, or if the rectangle is
// outside of the source picture.
// The rectangle for the view is defined by the top-left corner pixel
// coordinates (left, top) as well as its width and height. This rectangle
// must be fully be comprised inside the 'src' source picture. If the source
// picture uses the YUV420 colorspace, the top and left coordinates will be
// snapped to even values.
WEBP_EXTERN(int) WebPPictureCrop(WebPPicture* const picture,
int left, int top, int width, int height);
// Extracts a view from 'src' picture into 'dst'. The rectangle for the view
// is defined by the top-left corner pixel coordinates (left, top) as well
// as its width and height. This rectangle must be fully be comprised inside
// the 'src' source picture. If the source picture uses the YUV420 colorspace,
// the top and left coordinates will be snapped to even values.
// Picture 'src' must out-live 'dst' picture. Self-extraction of view is allowed
// ('src' equal to 'dst') as a mean of fast-cropping (but note that doing so,
// the original dimension will be lost).
// Returns false in case of memory allocation error or invalid parameters.
WEBP_EXTERN(int) WebPPictureView(const WebPPicture* const src,
int left, int top, int width, int height,
WebPPicture* const dst);
// Returns true if the 'picture' is actually a view and therefore does
// not own the memory for pixels.
WEBP_EXTERN(int) WebPPictureIsView(const WebPPicture* const picture);
// Rescale a picture to new dimension width x height.
// Now gamma correction is applied.
// Returns false in case of error (invalid parameter or insufficient memory).
@ -291,7 +321,7 @@ WEBP_EXTERN(int) WebPPictureRescale(WebPPicture* const pic,
// Colorspace conversion function to import RGB samples.
// Previous buffer will be free'd, if any.
// *rgb buffer should have a size of at least height * rgb_stride.
// Returns 0 in case of memory error.
// Returns false in case of memory error.
WEBP_EXTERN(int) WebPPictureImportRGB(
WebPPicture* const picture, const uint8_t* const rgb, int rgb_stride);
// Same, but for RGBA buffer.