| 1 | /* |
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| 2 | * Copyright 2007 Anthony Rowe and Adam Goode |
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| 3 | * |
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| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
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| 5 | * you may not use this file except in compliance with the License. |
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| 6 | * You may obtain a copy of the License at |
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| 7 | * |
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| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
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| 9 | * |
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| 10 | * Unless required by applicable law or agreed to in writing, software |
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| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
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| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 13 | * See the License for the specific language governing permissions and |
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| 14 | * limitations under the License. |
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| 15 | * |
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| 16 | */ |
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| 17 | |
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| 18 | |
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| 19 | #include "cc3.h" |
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| 20 | #include "cc3_ilp.h" |
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| 21 | #include "cc3_hsv.h" |
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| 22 | #include <stdbool.h> |
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| 23 | #include <stdio.h> |
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| 24 | |
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| 25 | |
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| 26 | |
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| 27 | |
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| 28 | /* |
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| 29 | * This function will convert an RGB pixel into a HSV pixel replacing the original |
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| 30 | * RGB value. |
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| 31 | * |
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| 32 | */ |
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| 33 | inline void cc3_rgb2hsv (cc3_pixel_t * pix) |
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| 34 | { |
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| 35 | uint8_t hue, sat, val; |
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| 36 | uint8_t rgb_min, rgb_max; |
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| 37 | rgb_max = 0; |
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| 38 | rgb_min = 255; |
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| 39 | if (pix->channel[CC3_CHANNEL_RED] > rgb_max) |
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| 40 | rgb_max = pix->channel[CC3_CHANNEL_RED]; |
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| 41 | if (pix->channel[CC3_CHANNEL_GREEN] > rgb_max) |
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| 42 | rgb_max = pix->channel[CC3_CHANNEL_GREEN]; |
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| 43 | if (pix->channel[CC3_CHANNEL_BLUE] > rgb_max) |
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| 44 | rgb_max = pix->channel[CC3_CHANNEL_BLUE]; |
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| 45 | if (pix->channel[CC3_CHANNEL_RED] < rgb_min) |
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| 46 | rgb_min = pix->channel[CC3_CHANNEL_RED]; |
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| 47 | if (pix->channel[CC3_CHANNEL_GREEN] < rgb_min) |
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| 48 | rgb_min = pix->channel[CC3_CHANNEL_GREEN]; |
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| 49 | if (pix->channel[CC3_CHANNEL_BLUE] < rgb_min) |
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| 50 | rgb_min = pix->channel[CC3_CHANNEL_BLUE]; |
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| 51 | |
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| 52 | // compute V |
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| 53 | val = rgb_max; |
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| 54 | if (val == 0) { |
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| 55 | hue = sat = 0; |
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| 56 | pix->channel[CC3_CHANNEL_HUE] = 0; |
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| 57 | pix->channel[CC3_CHANNEL_SAT] = 0; |
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| 58 | pix->channel[CC3_CHANNEL_VAL] = val; |
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| 59 | return; |
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| 60 | } |
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| 61 | |
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| 62 | // compute S |
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| 63 | sat = 255 * (rgb_max - rgb_min) / val; |
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| 64 | if (sat == 0) { |
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| 65 | pix->channel[CC3_CHANNEL_HUE] = 0; |
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| 66 | pix->channel[CC3_CHANNEL_SAT] = 0; |
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| 67 | pix->channel[CC3_CHANNEL_VAL] = val; |
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| 68 | return; |
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| 69 | } |
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| 70 | |
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| 71 | // compute H |
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| 72 | if (rgb_max == pix->channel[CC3_CHANNEL_RED]) { |
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| 73 | hue = |
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| 74 | 0 + 43 * (pix->channel[CC3_CHANNEL_GREEN] - |
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| 75 | pix->channel[CC3_CHANNEL_BLUE]) / (rgb_max - rgb_min); |
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| 76 | } |
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| 77 | else if (rgb_max == pix->channel[CC3_CHANNEL_GREEN]) { |
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| 78 | hue = |
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| 79 | 85 + 43 * (pix->channel[CC3_CHANNEL_BLUE] - |
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| 80 | pix->channel[CC3_CHANNEL_RED]) / (rgb_max - rgb_min); |
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| 81 | } |
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| 82 | else { /* rgb_max == blue */ |
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| 83 | |
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| 84 | hue = |
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| 85 | 171 + 43 * (pix->channel[CC3_CHANNEL_RED] - |
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| 86 | pix->channel[CC3_CHANNEL_GREEN]) / (rgb_max - rgb_min); |
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| 87 | } |
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| 88 | pix->channel[CC3_CHANNEL_HUE] = hue; |
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| 89 | pix->channel[CC3_CHANNEL_SAT] = sat; |
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| 90 | pix->channel[CC3_CHANNEL_VAL] = val; |
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| 91 | } |
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| 92 | |
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| 93 | void cc3_rgb2hsv_row (cc3_pixel_t * pix, uint16_t size) |
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| 94 | { |
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| 95 | uint16_t i; |
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| 96 | |
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| 97 | for (i = 0; i < size; i++) |
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| 98 | cc3_rgb2hsv (&pix[i]); |
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| 99 | |
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| 100 | } |
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