help! how to get RGB565 from RGB888?

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Hello anybody,
I need to get rgb565 from rgb888,because I want to show pictures on TFT,
I have tried the way like this

C++

#define COLOR_TO_MTK_COLOR_SIMUL(color) ((((color) >> 19) & 0x1f) \

                                            |((((color) >> 10) & 0x3f)  \

                                            |(((color) >> 3) & 0x1f)

but it is very bad method.

Is there anybody meet this problem?

Posted 9-Mar-12 21:26pm

wu_jin_liang

Updated 10-Mar-12 2:27am

Nelek

v2

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3 solutions

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nv3 · Answer 1 · 2012-03-10T00:08:00

Appears to me that you extracted the color components correctly but forgot to shift the components back into place to form the RGB565 format.

inline unsigned RGB888_to_RGB565 (unsigned rgb)
{
    return 
        (((rgb >> 19) & 0x1f) << 11) |
        (((rgb >> 10) & 0x3f) <<  6) |
        (((rgb >>  3) & 0x1f)      );
}

Is that the reason you were getting bad results? If not, please tell in which way the results you got were too bad or unexpected.

sherckuith · Answer 2 · 2012-04-04T17:18:00

Hi, i found a error:

C++

unsigned long RGB888_to_RGB565 (unsigned long rgb)
{
    return
        (((rgb >> 19) & 0x1f) << 11) |//19+10+3=32  //000000000000000000011111  //00001F    //1111100000000000
        (((rgb >> 10) & 0x3f) <<  5) |              //000000000011111111111111  //003FFF    //0000011111100000
        (((rgb >>  3) & 0x1f)      );               //000111111111111111111111  //1FFFFF    //
}

int main() {
    long color = RGB888_to_RGB565(0x0000ff);
    pc.printf("%X\n",color);
}

No is 6, is 5. Tank you for you code, it help me to solve a great problem in my job, its my contribution for you.
Bye my friend...

sherckuith · Answer 3 · 2012-04-04T17:36:00

Hello friends, may be it can help:

C++

Serial pc(USBTX,USBRX);

unsigned int RGB565CONVERT(int r,int g,int b,const char* color) {
    long RGB565;

    RGB565=(((r&0xF8)<<8)|((g&0xFC)<<3)|((b&0xF8)>>3));
    pc.printf("#define  %s      0x%0.4X\n",color,RGB565);
    return RGB565;
}

unsigned int RGB888_to_RGB565 (unsigned long rgb,const char* color) {
    long RGB565;

    RGB565= (((rgb >> 19) & 0x1f) << 11)|(((rgb >> 10) & 0x3f) <<  5)|(((rgb >>  3) & 0x1f));
    pc.printf("#define  %s      0x%0.4X\n",color,RGB565);
    return RGB565;
}

int main() {
    //long color = RGB888_to_RGB565(0x0000ff);
    //pc.printf("%X\n",color);
    RGB888_to_RGB565(0x0000ff,"BRIGHTBLUE");
    RGB565CONVERT(0,0,0,"NEGRO");
    RGB565CONVERT(0,0,255,"BRIGHTBLUE");
    RGB565CONVERT(0,255,0,"BRIGHTGREEN");
    RGB565CONVERT(0,255,255,"BRIGHTCYAN");
    RGB565CONVERT(255,0,0,"BRIGHTRED");
    RGB565CONVERT(255,0,255,"BRIGHTMAGENTA");
    RGB565CONVERT(255,255,0,"BRIGHTYELLOW");
    RGB565CONVERT(0,0,128,"AZUL");
    RGB565CONVERT(0,128,0,"VERDE");
    RGB565CONVERT(0,128,128,"CIAN");
    RGB565CONVERT(128,0,0,"ROJO");
    RGB565CONVERT(128,0,128,"MAGENTA");
    RGB565CONVERT(255,128,0,"BROWN");
    RGB565CONVERT(128,128,128,"gris_claro");
    RGB565CONVERT(64,64,64,"gris_oscuro");
    RGB565CONVERT(128,128,255,"lightblue");
    RGB565CONVERT(128,255,128,"verde_claro");
    RGB565CONVERT(128,255,255,"LIGHTCYAN");
    RGB565CONVERT(255,128,128,"LIGHTRED");
    RGB565CONVERT(255,128,255,"LIGHTMAGENTA");
    RGB565CONVERT(255,255,128,"AMARILLO");
    RGB565CONVERT(255,255,255,"BLANCO");
    RGB565CONVERT(224,224,224,"GRAY0");
    RGB565CONVERT(192,192,192,"GRAY1");
    RGB565CONVERT(160,160,160,"GRAY2");
    RGB565CONVERT(128,128,128,"GRAY3");
    RGB565CONVERT(96,96,96,"GRAY4");
    RGB565CONVERT(64,64,64,"GRAY5");
    RGB565CONVERT(32,32,32,"GRAY6");
    RGB565CONVERT(51,51,51,"GRAY20");
    RGB565CONVERT(102,102,102,"GRAY40");
    RGB565CONVERT(204,204,204,"GRAY80");
    RGB565CONVERT(229,229,229,"GRAY90");
    RGB565CONVERT(242,242,242,"GRAY95");
    RGB565CONVERT(139,0,0,"RED4");
    RGB565CONVERT(255,48,48,"FIREBRICK1");
    RGB565CONVERT(0,100,0,"DARKGREEN");
    RGB565CONVERT(152,251,152,"PALEGREEN");
    RGB565CONVERT(238,221,130,"LIGHTYELLOW");
    RGB565CONVERT(255,215,0,"GOLD");
    RGB565CONVERT(255,140,0,"DARKORANGE");
    
}

OUTPUT:

C++

#define  BRIGHTBLUE                       0x001F
#define  NEGRO      0x0000
#define  BRIGHTBLUE      0x001F
#define  BRIGHTGREEN      0x07E0
#define  BRIGHTCYAN      0x07FF
#define  BRIGHTRED      0xF800
#define  BRIGHTMAGENTA      0xF81F
#define  BRIGHTYELLOW      0xFFE0
#define  AZUL      0x0010
#define  VERDE      0x0400
#define  CIAN      0x0410
#define  ROJO      0x8000
#define  MAGENTA      0x8010
#define  BROWN      0xFC00
#define  gris_claro      0x8410
#define  gris_oscuro      0x4208
#define  lightblue      0x841F
#define  verde_claro      0x87F0
#define  LIGHTCYAN      0x87FF
#define  LIGHTRED      0xFC10
#define  LIGHTMAGENTA      0xFC1F
#define  AMARILLO      0xFFF0
#define  BLANCO      0xFFFF
#define  GRAY0      0xE71C
#define  GRAY1      0xC618
#define  GRAY2      0xA514
#define  GRAY3      0x8410
#define  GRAY4      0x630C
#define  GRAY5      0x4208
#define  GRAY6      0x2104
#define  GRAY20      0x3186
#define  GRAY40      0x632C
#define  GRAY80      0xCE79
#define  GRAY90      0xE73C
#define  GRAY95      0xF79E
#define  RED4      0x8800
#define  FIREBRICK1      0xF986
#define  DARKGREEN      0x0320
#define  PALEGREEN      0x9FD3
#define  LIGHTYELLOW      0xEEF0
#define  GOLD      0xFEA0
#define  DARKORANGE      0xFC60

****************************************Copy into code such as it be***************************
PD: sorry, my english not is good... i am Ecuatorian, i talk spanish.... Copien tal como esta el codigo en su programa...

help! how to get RGB565 from RGB888?

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