118
Six scan pixels were selected from the 72 nd and 73 rd row
of the pixmap and they are decreased in one case (67%
zoom out) and increased in two cases (170% and 800%
zoom in).
pixels and screen pixels is more complex than it may
appear to be at the first glance.
So, for example, raster graphics are not shown on the
Pixmap
17" screen with shadow mask
640x480 (a=0,22, b=0,15, a
co
CO
o'
ll
co
ll
N = 0,67
(67%-decrease)
N = 1,7
(170%-lncrease)
N = 8
(800%-increase)
x
f(x)
g(y)
u
v
f(x)
g(y)
u
V
f(x)
g(y)
u
v
P 51,73
2x2/2=
4x5/2=
17x26/2=
2 Pixel
10 Pixel
221
Pixel
A
50
72
/3,97
156,22
73
156
187,69
396,39
187
396
883,23
1865,38
883
1865
B
51
73
/5,45
158,4C
75
158
191,44
401,90
191
401
900,89
1891,28
900
1891
P5273
1 x2/2=
4x5/2=
18x26/2=
1 Pixel
10 Pixel
234 Pixel
A
51
72
75,45
156,22
75
156
191,44
396,39
191
396
900,89
1865,38
900
1865
B
52
73
76,93
158,40
76
158
195,19
401,90
195
401
918,56
1891,28
918
1891
P5373
2x2/2=
3x5/2
=7,5
18x26/2=
2 Pixel
8 Pixel
234 Pixel
A
52
72
76,93
156,22
76
156
195,19
396,39
195
396
918,56
1865,38
918
1865
B
53
73
78,40
158,40
78
158
198,95
401,90
198
401
936,22
1891,28
936
1891
P5174
2x2/2=
4x6/2=
17x26/2=
2 Pixel
12 Pixel
221
Pixel
A
50
73
73,97
158,40
73
158
187,69
401,90
187
401
883,23
1891,28
883
1891
B
51
74
75,45
160,56
75
160
191,44
407,40
191
407
900,89
1917,19
900
191/
P5274
1x2/2=
4x6/2=
18x26/2=
1 Pixel
12 Pixel
234 Pixel
A
51
73
75,45
158,40
75
158
191,44
401,90
191
401
900,89
1891,28
900
1891
B
52
74
76,93
160,56
76
160
195,19
407,40
195
407
918,56
1917,19
918
1917
P5374
2x2/2=
3x6/2=
18x26/2=
2 Pixel
9 Pixel
234 Pixel
A
52
73
76,93
158,40
76
158
195,19
401,90
195
401
918,56
1891,28
918
1891
B
53
74
78,40
160,56
78
160
198,95
407,40
198
407
936,22
1917,19
936
1917
Table 10: Presentation of the translation of pixmap => screen at a decrease (zoom out 67%)
and increase (zoom in 170% and 800%) on the example of a 17” screen with shadow mask.
Upon the introduction of the half-row coordinate system,
the apertures of the shadow mask are found only in every
second field of rows and columns. Since each aperture on
the shadow mask corresponds to one screen pixel, it is
necessary to re-calculate the half-row fields into actual
screen pixels. This re-calculation is performed according
to the following rule:
(number of columns * number of rows) / 2 = number of
screen pixels
Exception: (odd number of columns * odd number of
rows) / 2 = .5
1. example: (1 * 1 ) / 2 = 0.5
- or 1 screen pixel;
- or none screen pixel (when (x + y) of the lower left
corner is an even number).
2. example: (3 * 3) / 2 = 4.5
- or 5 screen pixels
- or 4 screen pixels (when (x + y) of the lower left corner is
an even number).
3. example: (Pixel P53,73, 170%; see Table 10):
(198- 195) * 8401 - 396) / 2 = (3 * 5) / 2 = 7.5
In this case the lower left corner is A’ (195, 396): (x + y =
195 + 396 = 591). Therefore it must be rounded up higher:
7.5 => 8 pixels.
4. CONCLUSION
From the considerations of the problem carried out so far,
it becomes obvious that the interdependence of scan
screen in their actual size. They change their size
depending on the resolution and the size of the screen,
because a scan pixel with a fixed form and size is being
translated into a screen pixel whose form and size are
changeable.
Among other things, it is not recommendable to use
screen resolutions higher than those corresponding to the
mask apertures (dot pitch and aperture grill pitch) are,
because it does not contribute to the quality of the image,
especially not with the screens with a shadow mask
(Malic, 1998).
5. REFERENCE
Foley, J.D., Dam, A. van, Feiner, S.K., Hughes, J.F.,
Philips, R.L., 1994. Grundlagen der Computergraphik:
Einführung, Methodne, Prinzipien - 1. Aufl., Addison-
Wesley, Bonn, Paris.
Lang, H., 1995. Farbwiedergabe in den Medien:
Fernsehen, Film, Druck, Muster-Schmidt Verl., Göttingen,
Zürich,
Malic, B., 1998. Physiologische und technische Aspekte
kartographischer Bildschirmvisualisierung, Diss. Schrift
Univ. Bonn, SIKB Heft 25.
Moers, S., Theißing, F., 1996. Der richtige Bildschirm.
Marktübersicht über strahlungarme, ergonomisch
empfehlenswerte Computerbildschirme, DGB
Technologieberatung e.V., Berlin.
