diff options
Diffstat (limited to 'drivers/webp/utils/rescaler.h')
| -rw-r--r-- | drivers/webp/utils/rescaler.h | 87 |
1 files changed, 56 insertions, 31 deletions
diff --git a/drivers/webp/utils/rescaler.h b/drivers/webp/utils/rescaler.h index 9c9133d19b..868467b4d7 100644 --- a/drivers/webp/utils/rescaler.h +++ b/drivers/webp/utils/rescaler.h @@ -1,8 +1,10 @@ // Copyright 2012 Google Inc. All Rights Reserved. // -// This code is licensed under the same terms as WebM: -// Software License Agreement: http://www.webmproject.org/license/software/ -// Additional IP Rights Grant: http://www.webmproject.org/license/additional/ +// Use of this source code is governed by a BSD-style license +// that can be found in the COPYING file in the root of the source +// tree. An additional intellectual property rights grant can be found +// in the file PATENTS. All contributing project authors may +// be found in the AUTHORS file in the root of the source tree. // ----------------------------------------------------------------------------- // // Rescaling functions @@ -12,64 +14,87 @@ #ifndef WEBP_UTILS_RESCALER_H_ #define WEBP_UTILS_RESCALER_H_ -#if defined(__cplusplus) || defined(c_plusplus) +#ifdef __cplusplus extern "C" { #endif -#include "../types.h" +#include "webp/types.h" + +#define WEBP_RESCALER_RFIX 32 // fixed-point precision for multiplies +#define WEBP_RESCALER_ONE (1ull << WEBP_RESCALER_RFIX) +#define WEBP_RESCALER_FRAC(x, y) \ + ((uint32_t)(((uint64_t)(x) << WEBP_RESCALER_RFIX) / (y))) // Structure used for on-the-fly rescaling -typedef struct { +typedef uint32_t rescaler_t; // type for side-buffer +typedef struct WebPRescaler WebPRescaler; +struct WebPRescaler { int x_expand; // true if we're expanding in the x direction + int y_expand; // true if we're expanding in the y direction int num_channels; // bytes to jump between pixels - int fy_scale, fx_scale; // fixed-point scaling factor - int64_t fxy_scale; // '' - // we need hpel-precise add/sub increments, for the downsampled U/V planes. + uint32_t fx_scale; // fixed-point scaling factors + uint32_t fy_scale; // '' + uint32_t fxy_scale; // '' int y_accum; // vertical accumulator - int y_add, y_sub; // vertical increments (add ~= src, sub ~= dst) - int x_add, x_sub; // horizontal increments (add ~= src, sub ~= dst) + int y_add, y_sub; // vertical increments + int x_add, x_sub; // horizontal increments int src_width, src_height; // source dimensions int dst_width, dst_height; // destination dimensions + int src_y, dst_y; // row counters for input and output uint8_t* dst; int dst_stride; - int32_t* irow, *frow; // work buffer -} WebPRescaler; + rescaler_t* irow, *frow; // work buffer +}; // Initialize a rescaler given scratch area 'work' and dimensions of src & dst. -void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height, +void WebPRescalerInit(WebPRescaler* const rescaler, + int src_width, int src_height, uint8_t* const dst, int dst_width, int dst_height, int dst_stride, int num_channels, - int x_add, int x_sub, - int y_add, int y_sub, - int32_t* const work); + rescaler_t* const work); + +// If either 'scaled_width' or 'scaled_height' (but not both) is 0 the value +// will be calculated preserving the aspect ratio, otherwise the values are +// left unmodified. Returns true on success, false if either value is 0 after +// performing the scaling calculation. +int WebPRescalerGetScaledDimensions(int src_width, int src_height, + int* const scaled_width, + int* const scaled_height); -// Import a row of data and save its contribution in the rescaler. -// 'channel' denotes the channel number to be imported. -void WebPRescalerImportRow(WebPRescaler* const rescaler, - const uint8_t* const src, int channel); +// Returns the number of input lines needed next to produce one output line, +// considering that the maximum available input lines are 'max_num_lines'. +int WebPRescaleNeededLines(const WebPRescaler* const rescaler, + int max_num_lines); // Import multiple rows over all channels, until at least one row is ready to // be exported. Returns the actual number of lines that were imported. int WebPRescalerImport(WebPRescaler* const rescaler, int num_rows, const uint8_t* src, int src_stride); -// Return true if there is pending output rows ready. +// Export as many rows as possible. Return the numbers of rows written. +int WebPRescalerExport(WebPRescaler* const rescaler); + +// Return true if input is finished static WEBP_INLINE -int WebPRescalerHasPendingOutput(const WebPRescaler* const rescaler) { - return (rescaler->y_accum <= 0); +int WebPRescalerInputDone(const WebPRescaler* const rescaler) { + return (rescaler->src_y >= rescaler->src_height); +} +// Return true if output is finished +static WEBP_INLINE +int WebPRescalerOutputDone(const WebPRescaler* const rescaler) { + return (rescaler->dst_y >= rescaler->dst_height); } -// Export one row from rescaler. Returns the pointer where output was written, -// or NULL if no row was pending. -uint8_t* WebPRescalerExportRow(WebPRescaler* const wrk); - -// Export as many rows as possible. Return the numbers of rows written. -int WebPRescalerExport(WebPRescaler* const wrk); +// Return true if there are pending output rows ready. +static WEBP_INLINE +int WebPRescalerHasPendingOutput(const WebPRescaler* const rescaler) { + return !WebPRescalerOutputDone(rescaler) && (rescaler->y_accum <= 0); +} //------------------------------------------------------------------------------ -#if defined(__cplusplus) || defined(c_plusplus) +#ifdef __cplusplus } // extern "C" #endif |