[emWin]How do I output a bmp image with a transparent color to the LCD?

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    • [emWin]How do I output a bmp image with a transparent color to the LCD?

      Dear all,
      I'd like to print the bmp-picture with transparent RGB-color value(0xFF00FF) on the background bmp and then print them all on the LCD.
      How do I implement it with emWin?

      image-data(testbg.bmp and num_w....bmp) are 16bit, 565 formated bmp.

      When I try test_trans1 function as below , transparent area also printed on lcd.

      //-----------------------TEST CODE--------------------//
      void test_trans1(....){
      GUI_SelectLayer(1);
      hMem = GUI_MEMDEV_CreateEx(x0, y0, xSize, ySize, GUI_MEMDEV_HASTRANS);
      GUI_MEMDEV_Select(hMem);

      GUI_SetBkColor(0xFFFF00FF);//Transparent Color?
      ...
      ..
      for(int i=0; i< max_images; i++){
      // set "bm_array" and "Bmp" with bmp-info
      GUI_DrawBitmap( (GUI_BITMAP*)&bm_array, &Bmp[i]->Left, (&Bmp[i]->Top) );
      }
      GUI_MEMDEV_Select(0);
      GUI_MEMDEV_CopyToLCD(hMem);
      GUI_MEMDEV_Delete(hMem);
      }
      //----------------------------------------------------------//

      Do anyone happen to know what's problem on emWin lib?

      Actually this kind of job to manipulate transparent color, is not that difficult,
      but It's frustrating that I can't check inside of draw function.

      Thanks in advance for your help.
      Best Regards,
      Tommy
      Files
      • testbg.bmp

        (1.11 kB, downloaded 26 times, last: )
      • num_w_transcolor.bmp

        (1.11 kB, downloaded 23 times, last: )

      The post was edited 2 times, last by Tommy lim ().

    • Hi,

      I'm wondering if "bm_array" is an actual BMP image file? Please note that the GUI_DrawBitmap() function is only for C bitmaps (the GUI_BITMAP structure), not actual BMP files.

      BMP images have to be drawn with the GUI_BMP_... API functions. You can find an example in our wiki on how to draw a BMP image file.

      Best regards,
      Florian
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