轉: RGB565、RGB888互相轉換原理和程式碼
轉:http://www.xuebuyuan.com/935987.html
背景:在我們的計算機中影象是以RGB888格式顯示影象的,24點陣圖每個畫素儲存了32bit的資料,即RGB888+Alpha,Alpha就是半透明填充位元組……但是對於真彩的影象而言,肉眼在16bit的時候已經難以分辨了,因此,有些時候,可以講RGB888轉換為RGB565來儲存,減少了儲存器的容量的同時,降低了資料量;在後端顯示的時候,再次把RGB565轉換為RGB888,實現資料寬度的匹配!!
題記: 總的思想就是,低位增加或者移除。
一.RGB888->RGB565
方法只要提取相應單色高位即可(R5 G6 B5),但會導致低位的缺失,影響精度,而且無法恢復。
二.RGB565->RGB888
方法只要補充相應單色低位即可(R3 G2 B3)。
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | R7 | R6 | R5 | R4 | R3 | R2 | R1 | R0 | G7 | G6 | G5 | G4 |
G3 | G2 | G1 | G0 | B7 | B6 | B5 | B4 | B3 | B2 | B1 | B0 |
R7 | R6 | R5 | R4 | R3 | G7 | G6 | G5 | G4 | G3 | G2 | B7 | B6 | B5 | B4 | B3 |
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#define RGB888_RED 0x00ff0000
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#define RGB888_GREEN 0x0000ff00
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#define RGB888_BLUE 0x000000ff
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#define RGB565_RED 0xf800
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#define RGB565_GREEN 0x07e0
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#define RGB565_BLUE 0x001f
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unsigned short RGB888ToRGB565(unsigned int n888Color)
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{
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unsigned short n565Color = 0;
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// 獲取RGB單色,並擷取高位
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unsigned char cRed = (n888Color & RGB888_RED) >> 19;
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unsigned char cGreen = (n888Color & RGB888_GREEN) >> 10;
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unsigned char cBlue = (n888Color & RGB888_BLUE) >> 3;
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// 連線
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n565Color = (cRed << 11) + (cGreen << 5) + (cBlue << 0);
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return n565Color;
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}
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unsigned int RGB565ToRGB888(unsigned short n565Color)
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{
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unsigned int n888Color = 0;
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// 獲取RGB單色,並填充低位
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unsigned char cRed = (n565Color & RGB565_RED) >> 8;
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unsigned char cGreen = (n565Color & RGB565_GREEN) >> 3;
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unsigned char cBlue = (n565Color & RGB565_BLUE) << 3;
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// 連線
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n888Color = (cRed << 16) + (cGreen << 8) + (cBlue << 0);
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return n888Color;
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}