From: Kaggen <kaggen_at_gmail.com>
Date: Mon, 21 Nov 2005 16:23:52 +0100

Hi,
I'm working on a homebrew system and I'm using the same
screen (controller-wise) as the iRiver H300.

If anyone feels like it you can test this code for functionality
& perfomance. But first let me say: sorry, I don't mean to use
you as alpha testers for my code, but I don't have any
hardware to test on at the moment.

So far i've toyed with lcd_update. I'm working on lcd_blit (which
is unimplemented in rockbox atm.)

If someone feels like explaining the fb_data buffer pixel layout
for me, I'd be happy aswell. At first I thought it was used for
rendering fonts, despite it's name.

It looks optimized for such use, since it renders an area using
8 pixels high rows, but I just realized that is a 8->16bit conversion
and not 8x 1->2bpp (which is perfect for B/W fonts).

Regards,
Anders

Next time I'll make a patch instead:
###################################

void lcd_update_rect(int x, int y, int width, int height)
{
    int ymax = y + height;

    if(x + width > LCD_WIDTH)
        width = LCD_WIDTH - x;
    if (width <= 0)
        return; /* nothing left to do, 0 is harmful to lcd_write_data() */
    if(ymax >= LCD_HEIGHT)
        ymax = LCD_HEIGHT-1;

    /* set update window */
    lcd_write_reg(0x44, (ymax<<8) | y); /* horiz ram addr */
    lcd_write_reg(0x45, ((x+width-1)<<8) | x); /* vert ram addr */
    lcd_write_reg(0x21, (x<<8) | y);
    lcd_begin_write_gram();

    /* Copy specified rectangle bitmap to hardware */
    for (; y <= ymax; y++)
    {
        lcd_write_data ((unsigned short *)&lcd_framebuffer[y][x], width);
    }

    /* reset update window */
    lcd_write_reg(0x44, 0xaf00); /* horiz ram addr */
    lcd_write_reg(0x45, 0xdb00); /* vert ram addr */
}

###################################
Received on 2005-11-21