In the current version of your TFT library, there is an unnecessary loop inside the drawString() function (lines 548-564 in the TFT.cpp source file). This is the current code:
[code]void TFT::drawString(char *string,unsigned int poX, unsigned int poY,unsigned int size,unsigned int fgcolor)
{
while(*string)
{
for(unsigned char i=0;i<8;i++)
{
drawChar(*string, poX, poY, size, fgcolor);
}
*string++;
if(poX < MAX_X)
{
poX+=8*size; // Move cursor right
}
}
}[/code]
The ‘for i’ loop is unnecessary; probably an accidental cut-and-paste from the drawChar() function, which needs a loop to draw the 8x8 character matrix. As a result, strings display properly, but take eight times longer than they need to to draw.
Simply deleting the loop as follows speeds string display up by a factor of eight:
[code]void TFT::drawString(char *string,unsigned int poX, unsigned int poY,unsigned int size,unsigned int fgcolor)
{
while(*string)
{
drawChar(*string, poX, poY, size, fgcolor);
*string++;
if(poX < MAX_X)
{
poX+=8*size; // Move cursor right
}
}
}[/code]
This makes a huge difference: on my 328-based Seeeduino, drawing strings goes from being a fairly slow process that you can actually see happening, to a much faster process that feels close to instantaneous.
May I suggest that you update the library to reflect this change? Anyone using the current version can fix this themselves by editing the TFT.cpp file in {Your Arduino work directory}/libraries/TFT/
,Many thanks.