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Implement "corner to corner" Gradient ellipses

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Thomas Bernard
2018-03-07 01:38:51 +01:00
parent c1afa188a2
commit df73e91c08
3 changed files with 116 additions and 0 deletions
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77
src/graph.c
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@@ -2,6 +2,7 @@
*/
/* Grafx2 - The Ultimate 256-color bitmap paint program
Copyright 2018 Thomas Bernard
Copyright 2008 Franck Charlet
Copyright 2007-2017 Adrien Destugues
Copyright 1996-2001 Sunset Design (Guillaume Dorme & Karl Maritaud)
@@ -2435,6 +2436,82 @@ void Draw_grad_ellipse(short center_x,short center_y,short horizontal_radius,sho
Update_part_of_screen(start_x,start_y,end_x-start_x+1,end_y-start_y+1);
}
void Draw_grad_inscribed_ellipse(short x1, short y1, short x2, short y2, short spot_x, short spot_y)
{
short left, right, top, bottom;
short dbl_center_x; // double of center_x
short dbl_center_y; // double of center_y
short dbl_x_radius; // double of horizontal radius
short dbl_y_radius; // double of vertical radius
long sq_dbl_x_radius;
long sq_dbl_y_radius;
qword sq_dbl_radius_product;
short x_pos;
short y_pos;
long sq_dist_x; // Square horizontal distance with the lightning point
long sq_dist_y; // Square vertical distance with the lightning point
if (x1 > x2)
{
left = x2;
right = x1;
}
else
{
left = x1;
right = x2;
}
if (y1 > y2)
{
top = y2;
bottom = y1;
}
else
{
top = y1;
bottom = y2;
}
dbl_center_x = left+right;
dbl_center_y = top+bottom;
dbl_x_radius = right-left+1;
dbl_y_radius = bottom-top+1;
sq_dbl_x_radius = (long)dbl_x_radius*dbl_x_radius;
sq_dbl_y_radius = (long)dbl_y_radius*dbl_y_radius;
sq_dbl_radius_product = (qword)sq_dbl_x_radius * sq_dbl_y_radius;
// calculate grandient range
Gradient_total_range= (sq_dbl_x_radius + sq_dbl_y_radius) / 4 +
((dbl_center_x/2-spot_x)*(dbl_center_x/2-spot_x))+
((dbl_center_y/2-spot_y)*(dbl_center_y/2-spot_y))+
(sqrt(sq_dbl_x_radius + sq_dbl_y_radius)
*sqrt(
((dbl_center_x/2-spot_x)*(dbl_center_x/2-spot_x))+
((dbl_center_y/2-spot_y)*(dbl_center_y/2-spot_y))));
if (Gradient_total_range==0)
Gradient_total_range=1;
for (y_pos = top; y_pos <= bottom; y_pos++)
{
long dbl_y = 2*y_pos - dbl_center_y;
long sq_dbl_y = dbl_y*dbl_y;
sq_dist_y =(y_pos-spot_y);
sq_dist_y *= sq_dist_y;
for (x_pos = left; x_pos <= right; x_pos++)
{
long dbl_x = 2*x_pos - dbl_center_x;
long sq_dbl_x = dbl_x*dbl_x;
if (((qword)sq_dbl_x * sq_dbl_y_radius + (qword)sq_dbl_y * sq_dbl_x_radius) < sq_dbl_radius_product)
{
sq_dist_x =(x_pos-spot_x);
sq_dist_x *= sq_dist_x;
Gradient_function(sq_dist_x+sq_dist_y,x_pos,y_pos);
}
}
}
Update_part_of_screen(left, top, right-left+1, bottom-top+1);
}
// Tracé d'un rectangle (rax ray - rbx rby) dégradé selon le vecteur (vax vay - vbx - vby)
void Draw_grad_rectangle(short rax,short ray,short rbx,short rby,short vax,short vay, short vbx, short vby)