forked from KolibriOS/kolibrios
113 lines
2.8 KiB
Plaintext
113 lines
2.8 KiB
Plaintext
==========================================
|
|
The Scale2x, Scale3x and Scale4x algorithm
|
|
==========================================
|
|
|
|
|
|
SCALE2X ALGORITHM
|
|
=================
|
|
|
|
The effect works repeating a computation pattern for every
|
|
pixel of the original image.
|
|
The pattern starts from a square of 9 pixels and expands the
|
|
central pixel computing 4 new pixels.
|
|
|
|
Starting from this pattern :
|
|
|
|
A B C
|
|
D E F
|
|
G H I
|
|
|
|
The central pixel E is expanded in 4 new pixels:
|
|
|
|
E0 E1
|
|
E2 E3
|
|
|
|
with these rules (in C language) :
|
|
|
|
E0 = D == B && B != F && D != H ? D : E;
|
|
E1 = B == F && B != D && F != H ? F : E;
|
|
E2 = D == H && D != B && H != F ? D : E;
|
|
E3 = H == F && D != H && B != F ? F : E;
|
|
|
|
which can be rewritten as :
|
|
|
|
E0 = D == B && B != H && D != F ? D : E;
|
|
E1 = B == F && B != H && D != F ? F : E;
|
|
E2 = D == H && B != H && D != F ? D : E;
|
|
E3 = H == F && B != H && D != F ? F : E;
|
|
|
|
and optimized as:
|
|
|
|
if (B != H && D != F) {
|
|
E0 = D == B ? D : E;
|
|
E1 = B == F ? F : E;
|
|
E2 = D == H ? D : E;
|
|
E3 = H == F ? F : E;
|
|
} else {
|
|
E0 = E;
|
|
E1 = E;
|
|
E2 = E;
|
|
E3 = E;
|
|
}
|
|
|
|
The image border is computed reusing the value of the nearest pixel
|
|
on the border when the value of a pixel over the border is required.
|
|
|
|
|
|
SCALE3X ALGORITHM
|
|
=================
|
|
|
|
Starting from this pattern :
|
|
|
|
A B C
|
|
D E F
|
|
G H I
|
|
|
|
The central pixel E is expanded in 9 new pixels:
|
|
|
|
E0 E1 E2
|
|
E3 E4 E5
|
|
E6 E7 E8
|
|
|
|
with these rules (in C language) :
|
|
|
|
E0 = D == B && B != F && D != H ? D : E;
|
|
E1 = (D == B && B != F && D != H && E != C) || (B == F && B != D && F != H && E != A) ? B : E;
|
|
E2 = B == F && B != D && F != H ? F : E;
|
|
E3 = (D == B && B != F && D != H && E != G) || (D == H && D != B && H != F && E != A) ? D : E;
|
|
E4 = E
|
|
E5 = (B == F && B != D && F != H && E != I) || (H == F && D != H && B != F && E != C) ? F : E;
|
|
E6 = D == H && D != B && H != F ? D : E;
|
|
E7 = (D == H && D != B && H != F && E != I) || (H == F && D != H && B != F && E != G) ? H : E;
|
|
E8 = H == F && D != H && B != F ? F : E;
|
|
|
|
and optimized as:
|
|
|
|
if (B != H && D != F) {
|
|
E0 = D == B ? D : E;
|
|
E1 = (D == B && E != C) || (B == F && E != A) ? B : E;
|
|
E2 = B == F ? F : E;
|
|
E3 = (D == B && E != G) || (D == H && E != A) ? D : E;
|
|
E4 = E;
|
|
E5 = (B == F && E != I) || (H == F && E != C) ? F : E;
|
|
E6 = D == H ? D : E;
|
|
E7 = (D == H && E != I) || (H == F && E != G) ? H : E;
|
|
E8 = H == F ? F : E;
|
|
} else {
|
|
E0 = E;
|
|
E1 = E;
|
|
E2 = E;
|
|
E3 = E;
|
|
E4 = E;
|
|
E5 = E;
|
|
E6 = E;
|
|
E7 = E;
|
|
E8 = E;
|
|
}
|
|
|
|
|
|
SCALE4X ALGORITHM
|
|
=================
|
|
|
|
The Scale4x effect is simply the Scale2x effect applied two times.
|