static void
event_help( void )
{
grEvent dummy_event;
FTDemo_Display_Clear( display );
grSetLineHeight( 10 );
grGotoxy( 0, 0 );
grSetMargin( 2, 1 );
grGotobitmap( display->bitmap );
grWriteln( "FreeType String Viewer - part of the FreeType test suite" );
grLn();
grWriteln( "This program is used to display a string of text using" );
grWriteln( "the new convenience API of the FreeType 2 library." );
grLn();
grWriteln( "Use the following keys :" );
grLn();
grWriteln( " F1 or ? : display this help screen" );
grLn();
grWriteln( " a : toggle anti-aliasing" );
grWriteln( " b : toggle embedded bitmaps (and disable rotation)" );
grWriteln( " f : toggle forced auto-hinting" );
grWriteln( " h : toggle outline hinting" );
grLn();
grWriteln( " 1-2 : select rendering mode" );
grWriteln( " k : cycle through kerning modes" );
grWriteln( " t : cycle through kerning degrees" );
grWriteln( " V : toggle vertical rendering" );
grLn();
grWriteln( " G : toggle gamma correction" );
grWriteln( " g : increase gamma by 0.1" );
grWriteln( " v : decrease gamma by 0.1" );
grLn();
grWriteln( " n : next font" );
grWriteln( " p : previous font" );
grLn();
grWriteln( " Up : increase pointsize by 1 unit" );
grWriteln( " Down : decrease pointsize by 1 unit" );
grWriteln( " Page Up : increase pointsize by 10 units" );
grWriteln( " Page Down : decrease pointsize by 10 units" );
grLn();
grWriteln( " Right : rotate counter-clockwise" );
grWriteln( " Left : rotate clockwise" );
grWriteln( " F7 : big rotate counter-clockwise" );
grWriteln( " F8 : big rotate clockwise" );
grLn();
grWriteln( "press any key to exit this help screen" );
grRefreshSurface( display->surface );
grListenSurface( display->surface, gr_event_key, &dummy_event );
}
static FT_Error
Render_GammaGrid( grBitmap* bitmap )
{
int g;
int xmargin = 10;
int gamma_first = 16;
int gamma_last = 26;
int gammas = gamma_last - gamma_first + 1;
int xside = (bitmap->width-100)/gammas - xmargin;
int yside = (bitmap->rows-100)/2;
int yrepeat = 1;
int x_0 = (bitmap->width - gammas*(xside+xmargin)+xmargin)/2;
int y_0 = (bitmap->rows - (8+yside*2*yrepeat))/2;
int pitch = bitmap->pitch;
if ( pitch < 0 )
pitch = -pitch;
#if 1
memset( bitmap->buffer, 255, pitch*bitmap->rows );
#else
/* fill the background with a simple pattern corresponding to 50%
* linear gray from a reasonable viewing distance
*/
{
int nx, ny;
unsigned char* line = bitmap->buffer;
if ( bitmap->pitch < 0 )
line -= (bitmap->pitch*(bitmap->rows-1));
for ( ny = 0; ny < bitmap->rows; ny++, line += bitmap->pitch )
{
unsigned char* dst = line;
int nx;
for ( nx = 0; nx < bitmap->width; nx++, dst += 3 )
{
int color = ((nx+ny) & 1)*255;
dst[0] = dst[1] = dst[2] = (unsigned char)color;
}
}
}
#endif
grGotobitmap( bitmap );
for ( g = gamma_first; g <= gamma_last; g += 1 )
{
double gamma_value = g/10.0;
char temp[6];
int x = x_0 + (xside+xmargin)*(g-gamma_first);
int y = y_0;
int ny;
grSetPixelMargin( x, y_0-8 );
grGotoxy( 0, 0 );
sprintf( temp, "%.1f", gamma_value );
grWrite( temp );
for ( ny = 0; ny < yrepeat; ny++, y += 2*yside )
{
do_rect( bitmap, x, y, xside, yside,
(int)( 255.0 * pow( 0.5, 1.0 / gamma_value ) ) );
do_rect( bitmap, x, y+yside, xside, yside, -1 );
}
}
return 0;
}
