rectangle transparency

[bobtrex]

I am probably missing something very basic

but with the code below, why is the black rectangle 50% transparent ?

Thanks and Regards



#include <EEPROM.h>
#include <SPI.h>

#include <GD2.h>





#define VX(x, y)  GD.Vertex2f(16 * (x), 16 * (y))

void setup()

{

 GD.begin(0);

}



void loop()

{

 delay(10000);

 GD.RestoreContext();

 GD.RestoreContext();

 GD.RestoreContext();

 GD.RestoreContext();

 GD.RestoreContext();

 GD.ClearColorRGB(0x103000);

 GD.Clear();

 GD.cmd_text(GD.w / 2, GD.h / 2, 31, OPT_CENTER, "Hello world");

 GD.ColorRGB(0xFF0000);  

 GD.Begin(LINES);

 GD.LineWidth(8);

 GD.Vertex2f(0,0);

 GD.Vertex2f(100*16,0);

 GD.Vertex2f(100*16,0);

 GD.Vertex2f(100*16,100*16);

 GD.Vertex2f(100*16,100*16);

 GD.Vertex2f(0,100*16);

 GD.Vertex2f(0,100*16);

 GD.Vertex2f(0,0);

 GD.Begin(RECTS);

 GD.ColorRGB(0x00ff00);

 VX(2, 2);

 VX(99, 99);

 GD.ColorRGB(0x0000FF);  

 GD.cmd_text(50, 50, 22, OPT_CENTER, "Hello world");





 GD.ColorRGB(0xFF0000);  

 GD.Begin(LINES);

 GD.LineWidth(8);

 VX(120,120);

 VX(220,120);

 VX(220,120);

 VX(220,220);

 VX(220,220);

 VX(120,220);

 VX(120,220);

 VX(120,120);

 //This rectange is 50% transparent regardless of GD.ColorA(255);

 GD.Begin(RECTS);

// GD.ColorA(255);

 GD.ColorRGB(0x000000);

 VX(122, 122);

 VX(219, 219);

 GD.ColorRGB(0x0000FF);  

 GD.cmd_text(170, 170, 22, OPT_CENTER, "Hello world");

 //GD.ColorA(128);

 GD.ColorRGB(0x0000FF);  

 GD.PointSize(16 * 30); // means 30 pixels

 GD.Begin(POINTS);

 GD.Vertex2ii(220, 100);

 GD.Vertex2ii(260, 170);

 GD.PointSize(16 * 8); // means 30 pixels

 GD.RestoreContext();

 //Not tranparrent

 GD.Begin(RECTS);

 //GD.ColorA(255);

 GD.ColorRGB(0x666666);

 VX(150, 150);

 VX(250, 250);

   

   //GD.ColorRGB(0xFFFFFF);

   //GD.cmd_text(GD.w / 2, GD.h / 2, 31, OPT_CENTER, "Hello world");

 GD.swap();

}

[jamesbowman]

The hardware's RECTANGLE  primitive draws round-cornered rectangles. The corner radius is specified by GD.LineWidth(), in 1/16th of a pixel, with a minimum radius of 1 pixel (i.e. no rounding at all). Values below 16 are invalid, and seem to draw a rectangle with a transparent interior:


GD.LineWidth(8);


The corner radius is better described in the book on p.50, but it does not mention that values below 16 are invalid.

excamera.com/files/gd2book_v0.pdf

[bobtrex]

Thanks for the prompt reply. Yep that did it. Thanks