//划线函数(有符号)
void Line( unsigned int y1, unsigned char x1, unsigned int y2, unsigned char x2, uint8 Mode)
{
unsigned char x,y,z;
float k,b;
if(x1==x2)
y_line(y1,x1, y2, Mode);
else if(y1==y2)
x_line(y1,x1, x2, Mode);
else
{
z=0;
{
signed int y_f,x_f;
y_f=(signed int)y2-(signed int)y1;
x_f=(signed int)x2-(signed int)x1;
if( abs(y_f)< abs(x_f) ) // |k|<=1
z=1;
}
if( z==1 ) // |k|<=1
{
{
signed int y_f,x_f;
y_f=(signed int)y2-(signed int)y1;
x_f=(signed int)x2-(signed int)x1;
k=(float)(y_f) / (float)(x_f) ;
b=(float)y1-k*(float)x1;
}
if( x1 < x2 )
{
z=y1;
for(x=x1+1;x<x2;x++)
{
y=(unsigned char)(k*(float)x+b);
Pixel(y, x, Mode);
y_line(y, x, z, Mode);
z=y;
}
}
else
{
z=y2;
for(x=x2+1;x<x1;x++)
{
y=(unsigned char)(k*(float)x+b);
Pixel(y, x, Mode);
y_line(y, x, z, Mode);
z=y;
}
}
}
else // abs(y1-y2) < abs(x1-x2) |K|>1
{
{
signed int y_f,x_f;
y_f=(signed int)y2-(signed int)y1;
x_f=(signed int)x2-(signed int)x1;
k=(float)x_f / (float)y_f ;
b=(float)x1-k*(float)y1;
}
if( y1 <= y2 )
{
z=x1;
for(y=y1+1;y<y2;y++)
{
x=(unsigned char)(k*(float)y+b);
Pixel( y , x,Mode );
x_line(y, x, z, Mode);
z=x;
}
}
else
{
z=x2;
for(y=y2+1;y<y1;y++)
{
x=(unsigned char)(k*(float)y+b);
Pixel( y, x,Mode );
x_line(y, x, z,Mode);
z=x;
}
}
}
}
}
static void
render_spect_border (cairo_surface_t * surface, const char * filename, double left, double width, double seconds, double top, double height, double min_freq, double max_freq, bool log_freq)
{
char text [512] ;
cairo_t * cr ;
cairo_text_extents_t extents ;
cairo_matrix_t matrix ;
TICKS ticks ;
int k, tick_count ;
cr = cairo_create (surface) ;
cairo_set_source_rgb (cr, 1.0, 1.0, 1.0) ;
cairo_set_line_width (cr, BORDER_LINE_WIDTH) ;
/* Print title. */
cairo_select_font_face (cr, font_family, CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL) ;
cairo_set_font_size (cr, 1.0 * TITLE_FONT_SIZE) ;
snprintf (text, sizeof (text), "Spectrogram: %s", filename) ;
cairo_text_extents (cr, text, &extents) ;
cairo_move_to (cr, left + 2, top - extents.height / 2) ;
cairo_show_text (cr, text) ;
/* Print labels. */
cairo_select_font_face (cr, font_family, CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL) ;
cairo_set_font_size (cr, 1.0 * NORMAL_FONT_SIZE) ;
/* Border around actual spectrogram. */
cairo_rectangle (cr, left, top, width, height) ;
/* Put ticks on Time axis */
tick_count = calculate_ticks (0.0, seconds, width, false, &ticks) ;
for (k = 0 ; k < tick_count ; k++)
{ y_line (cr, left + ticks.distance [k], top + height, TICK_LEN) ;
if (JUST_A_TICK (ticks, k))
continue ;
str_print_value (text, sizeof (text), ticks.value [k],
ticks.decimal_places_to_print) ;
cairo_text_extents (cr, text, &extents) ;
cairo_move_to (cr, left + ticks.distance [k] - extents.width / 2, top + height + 8 + extents.height) ;
cairo_show_text (cr, text) ;
} ;
/* Put ticks on Frequency axis */
tick_count = calculate_ticks (min_freq, max_freq, height, log_freq, &ticks) ;
for (k = 0 ; k < tick_count ; k++)
{ x_line (cr, left + width, top + height - ticks.distance [k], TICK_LEN) ;
if (JUST_A_TICK (ticks, k))
continue ;
str_print_value (text, sizeof (text), ticks.value [k],
ticks.decimal_places_to_print) ;
cairo_text_extents (cr, text, &extents) ;
cairo_move_to (cr, left + width + 12, top + height - ticks.distance [k] + extents.height / 4.5) ;
cairo_show_text (cr, text) ;
} ;
cairo_set_font_size (cr, 1.0 * NORMAL_FONT_SIZE) ;
/* Label X axis. */
snprintf (text, sizeof (text), "Time (secs)") ;
cairo_text_extents (cr, text, &extents) ;
cairo_move_to (cr, left + (width - extents.width) / 2, cairo_image_surface_get_height (surface) - 8) ;
cairo_show_text (cr, text) ;
/* Label Y axis (rotated). */
snprintf (text, sizeof (text), "Frequency (Hz)") ;
cairo_text_extents (cr, text, &extents) ;
cairo_get_font_matrix (cr, &matrix) ;
cairo_matrix_rotate (&matrix, -0.5 * M_PI) ;
cairo_set_font_matrix (cr, &matrix) ;
cairo_move_to (cr, cairo_image_surface_get_width (surface) - 12, top + (height + extents.width) / 2) ;
cairo_show_text (cr, text) ;
cairo_destroy (cr) ;
} /* render_spect_border */
