OLD | NEW |
1 // Copyright 2012 Google Inc. All Rights Reserved. | 1 // Copyright 2012 Google Inc. All Rights Reserved. |
2 // | 2 // |
3 // Use of this source code is governed by a BSD-style license | 3 // Use of this source code is governed by a BSD-style license |
4 // that can be found in the COPYING file in the root of the source | 4 // that can be found in the COPYING file in the root of the source |
5 // tree. An additional intellectual property rights grant can be found | 5 // tree. An additional intellectual property rights grant can be found |
6 // in the file PATENTS. All contributing project authors may | 6 // in the file PATENTS. All contributing project authors may |
7 // be found in the AUTHORS file in the root of the source tree. | 7 // be found in the AUTHORS file in the root of the source tree. |
8 // ----------------------------------------------------------------------------- | 8 // ----------------------------------------------------------------------------- |
9 // | 9 // |
10 // Rescaling functions | 10 // Rescaling functions |
11 // | 11 // |
12 // Author: Skal (pascal.massimino@gmail.com) | 12 // Author: Skal (pascal.massimino@gmail.com) |
13 | 13 |
14 #ifndef WEBP_UTILS_RESCALER_H_ | 14 #ifndef WEBP_UTILS_RESCALER_H_ |
15 #define WEBP_UTILS_RESCALER_H_ | 15 #define WEBP_UTILS_RESCALER_H_ |
16 | 16 |
17 #ifdef __cplusplus | 17 #ifdef __cplusplus |
18 extern "C" { | 18 extern "C" { |
19 #endif | 19 #endif |
20 | 20 |
21 #include "../webp/types.h" | 21 #include "../webp/types.h" |
22 | 22 |
| 23 #define WEBP_RESCALER_RFIX 32 // fixed-point precision for multiplies |
| 24 #define WEBP_RESCALER_ONE (1ull << WEBP_RESCALER_RFIX) |
| 25 #define WEBP_RESCALER_FRAC(x, y) \ |
| 26 ((uint32_t)(((uint64_t)(x) << WEBP_RESCALER_RFIX) / (y))) |
| 27 |
23 // Structure used for on-the-fly rescaling | 28 // Structure used for on-the-fly rescaling |
24 typedef uint32_t rescaler_t; // type for side-buffer | 29 typedef uint32_t rescaler_t; // type for side-buffer |
25 typedef struct { | 30 typedef struct WebPRescaler WebPRescaler; |
| 31 struct WebPRescaler { |
26 int x_expand; // true if we're expanding in the x direction | 32 int x_expand; // true if we're expanding in the x direction |
27 int y_expand; // true if we're expanding in the y direction | 33 int y_expand; // true if we're expanding in the y direction |
28 int num_channels; // bytes to jump between pixels | 34 int num_channels; // bytes to jump between pixels |
29 uint32_t fx_scale; // fixed-point scaling factors | 35 uint32_t fx_scale; // fixed-point scaling factors |
30 uint32_t fy_scale; // '' | 36 uint32_t fy_scale; // '' |
31 uint32_t fxy_scale; // '' | 37 uint32_t fxy_scale; // '' |
32 int y_accum; // vertical accumulator | 38 int y_accum; // vertical accumulator |
33 int y_add, y_sub; // vertical increments | 39 int y_add, y_sub; // vertical increments |
34 int x_add, x_sub; // horizontal increments | 40 int x_add, x_sub; // horizontal increments |
35 int src_width, src_height; // source dimensions | 41 int src_width, src_height; // source dimensions |
36 int dst_width, dst_height; // destination dimensions | 42 int dst_width, dst_height; // destination dimensions |
37 int src_y, dst_y; // row counters for input and output | 43 int src_y, dst_y; // row counters for input and output |
38 uint8_t* dst; | 44 uint8_t* dst; |
39 int dst_stride; | 45 int dst_stride; |
40 rescaler_t* irow, *frow; // work buffer | 46 rescaler_t* irow, *frow; // work buffer |
41 } WebPRescaler; | 47 }; |
42 | 48 |
43 // Initialize a rescaler given scratch area 'work' and dimensions of src & dst. | 49 // Initialize a rescaler given scratch area 'work' and dimensions of src & dst. |
44 void WebPRescalerInit(WebPRescaler* const rescaler, | 50 void WebPRescalerInit(WebPRescaler* const rescaler, |
45 int src_width, int src_height, | 51 int src_width, int src_height, |
46 uint8_t* const dst, | 52 uint8_t* const dst, |
47 int dst_width, int dst_height, int dst_stride, | 53 int dst_width, int dst_height, int dst_stride, |
48 int num_channels, | 54 int num_channels, |
49 rescaler_t* const work); | 55 rescaler_t* const work); |
50 | 56 |
| 57 // If either 'scaled_width' or 'scaled_height' (but not both) is 0 the value |
| 58 // will be calculated preserving the aspect ratio, otherwise the values are |
| 59 // left unmodified. Returns true on success, false if either value is 0 after |
| 60 // performing the scaling calculation. |
| 61 int WebPRescalerGetScaledDimensions(int src_width, int src_height, |
| 62 int* const scaled_width, |
| 63 int* const scaled_height); |
| 64 |
51 // Returns the number of input lines needed next to produce one output line, | 65 // Returns the number of input lines needed next to produce one output line, |
52 // considering that the maximum available input lines are 'max_num_lines'. | 66 // considering that the maximum available input lines are 'max_num_lines'. |
53 int WebPRescaleNeededLines(const WebPRescaler* const rescaler, | 67 int WebPRescaleNeededLines(const WebPRescaler* const rescaler, |
54 int max_num_lines); | 68 int max_num_lines); |
55 | 69 |
56 // Import multiple rows over all channels, until at least one row is ready to | 70 // Import multiple rows over all channels, until at least one row is ready to |
57 // be exported. Returns the actual number of lines that were imported. | 71 // be exported. Returns the actual number of lines that were imported. |
58 int WebPRescalerImport(WebPRescaler* const rescaler, int num_rows, | 72 int WebPRescalerImport(WebPRescaler* const rescaler, int num_rows, |
59 const uint8_t* src, int src_stride); | 73 const uint8_t* src, int src_stride); |
60 | 74 |
61 // Export as many rows as possible. Return the numbers of rows written. | 75 // Export as many rows as possible. Return the numbers of rows written. |
62 int WebPRescalerExport(WebPRescaler* const rescaler); | 76 int WebPRescalerExport(WebPRescaler* const rescaler); |
63 void WebPRescalerImportRow(WebPRescaler* const wrk, | |
64 const uint8_t* src); | |
65 // Export one row (starting at x_out position) from rescaler. | |
66 void WebPRescalerExportRow(WebPRescaler* const wrk); | |
67 | 77 |
68 // Return true if input is finished | 78 // Return true if input is finished |
69 static WEBP_INLINE | 79 static WEBP_INLINE |
70 int WebPRescalerInputDone(const WebPRescaler* const rescaler) { | 80 int WebPRescalerInputDone(const WebPRescaler* const rescaler) { |
71 return (rescaler->src_y >= rescaler->src_height); | 81 return (rescaler->src_y >= rescaler->src_height); |
72 } | 82 } |
73 // Return true if output is finished | 83 // Return true if output is finished |
74 static WEBP_INLINE | 84 static WEBP_INLINE |
75 int WebPRescalerOutputDone(const WebPRescaler* const rescaler) { | 85 int WebPRescalerOutputDone(const WebPRescaler* const rescaler) { |
76 return (rescaler->dst_y >= rescaler->dst_height); | 86 return (rescaler->dst_y >= rescaler->dst_height); |
77 } | 87 } |
78 | 88 |
79 // Return true if there are pending output rows ready. | 89 // Return true if there are pending output rows ready. |
80 static WEBP_INLINE | 90 static WEBP_INLINE |
81 int WebPRescalerHasPendingOutput(const WebPRescaler* const rescaler) { | 91 int WebPRescalerHasPendingOutput(const WebPRescaler* const rescaler) { |
82 return !WebPRescalerOutputDone(rescaler) && (rescaler->y_accum <= 0); | 92 return !WebPRescalerOutputDone(rescaler) && (rescaler->y_accum <= 0); |
83 } | 93 } |
84 | 94 |
85 //------------------------------------------------------------------------------ | 95 //------------------------------------------------------------------------------ |
86 | 96 |
87 #ifdef __cplusplus | 97 #ifdef __cplusplus |
88 } // extern "C" | 98 } // extern "C" |
89 #endif | 99 #endif |
90 | 100 |
91 #endif /* WEBP_UTILS_RESCALER_H_ */ | 101 #endif /* WEBP_UTILS_RESCALER_H_ */ |
OLD | NEW |