Автор: Mark C. Jones
Год: 1984
Издатели: Your Computer
Языки:
АнглийскийФормат:
TZX лентаТребования:
ZX Spectrum 48KСсылки:
Страница на ZXArt
Страница на World Of Spectrum
Страница на Spectrum ComputingСкриншоты:
Описание:
Zoom— это утилита на машинном коде, разработанная для ZX Spectrum 48K Марком С. Джонсом. Выпущенная в 1984 году, эта программа позволяет пользователям увеличивать определенные области экрана до полного размера, предоставляя инструмент увеличения для лучшей видимости. Размер окна может варьироваться от 8 до 256 пикселей в ширину и от 3 до 192 пикселей в высоту, предлагая гибкие настройки для различных нужд.
Программа работает, обращаясь к различным переменным Basic для своих параметров, устраняя необходимость в ручном вводе чисел. Она оснащена комплексной проверкой ошибок, чтобы гарантировать, что окно остается на экране, автоматически корректируя координаты и размеры, если они превышают допустимые значения. Эта функциональность делает её удобной и эффективной.
Zoom не увеличивает цвета, но сохраняет текущий постоянный цвет атрибута во время увеличения. Используемый алгоритм берет каждую строку окна, помещает её в буфер и удваивает ширину, пока она не достигнет 32 байт. Этот буфер затем отображается на экране несколько раз, создавая увеличенное изображение.
Основные команды включают очистку экранов, перемещение резервных экранов и изменение размеров окон. Машинные коды используются для различных манипуляций с экраном, обеспечивая плавную работу программы без внешнего управления. Zoom относится к системному программному обеспечению и графическим утилитам, опубликованным Your Computer.
ZOOM
ZOOM
ZOOM
Mark Jones takes you up, up and away... with this
instant enlarger for the bleary-eyed Spectrum.
Zoom is an easy to use machine-code utility and allows the
user to enlarge to full screen size the area of the screen
enclosed within a window. This window can be varied in size
from 8-256 pixels wide and from 3-192 pixels high. When in
Magnify mode the magnified area can be viewed continuously
as the window is moved. Since the magnified area can also
itself be magnified, using the same window, infinite magni-
fication is possible, even if of doubtful use. The routine
does not magnify the colour but produces the magnification
in the current permanent attribute colour.
The routine accesses various Basic variables for its
parameters. This means you do not have to bother Poking any
numbers, but just use a Let statement. If you call the
routine without having assigned the following variables a
"2 Variable not found" error will be given.
The machine code has comprehensive error checking. Zoom
will not allow XPos or YPos to be values that make a part
of the window go off screen. If, say, XPos was 270, an
illegal screen co-ordinate, Zoom would give XPos a new
value that ensured that the window was entirely on the
screen. This value would vary with the size of the window.
The width of the window can have values between 0 and 5,
the depth can have values between 0 and 6. If the variables
Width or Depth have values that are too big Zoom will
change the value to the maximum permissible value. Likewise
if either has a negative value Zoom will replace the value
with 0. The width and depth numbers correspond to the
following window sizes:
Width Depth
0 256 pixels 192 pixels
1 128 96
2 64 48
3 32 24
4 16 12
5 8 6
6 - 3
Thus to have a window size 64 pixels by 12 pixels, Width
would be 2 and depth would be 4. If you wish to see an
example of Zoom error correcting, load up Zoom code and
then run the following lines of Basic.
10 LET xpos=260: LET ypos=-10
20 LET width=6: LET depth=-5
Having run the program type
RANDOMIZE USR 50000
This will draw the Zoom window. In this case you will see a
very tall, thin window. If you now type PRINT XPos,YPos,
Width,Depth you will find that Width=5, Depth=0, XPos=248
and YPos=192. Since XPos and YPos denote the top left cor-
ner of the window, YPos has been made 192 since the window
is 192 pixels high, i.e., this is the first value of YPos
above -10 that allows the window to appear/sit on the
screen. XPos has been rounded down until the window is on
the screen, in this case 256-window width.
The algorithm used for Zoom takes each line of the
window, places it in a buffer and keeps on doubling it in
width until it is 32 bytes wide. It then puts the 32-byte
buffer down on the screen - 192/(window y size) - times.
The initial form of the screen is saved at 32768 and the
magnified image is formed on the normal screen, i.e., at
16384. To create Zoom, type in program A and then save it.
Now try running it, if you have no errors, then save the
code. The code can be used independently of program B; this
program is provided to help you use Zoom.
Basic program commands.
A ... Clear main screen and back-up.
B ... Move back-up screen down to current window screen.
L ... Load with new back-up screen.
m ... Magnify area under window until new key press.
M ... Continuously magnify. View can be moved around using
normal direction keys.
N ... Retrieve back-up screen.
P ... Make magnified image current window screen.
s ... Alter window movement step size.
x ... Increase window width.
X ... Decrease window width.
y ... Increase window depth.
Y ... Decrease window depth.
Machine-code routines.
Address
50000 XOR current window onto screen. Doing this twice
will delete the window
50003 Move screen from 32768 to 16384
50011 Move screen from 16384 to 32768
50019 Move screen from 39680 to 16384
50027 Move screen from 16384 to 39680
50039 Magnify area under window
The area 50708-50800 is used as workspace by Zoom and
should be left clear.
32768-39679 Used to store screen during magnification.
39680-46591 Used to store back-up screen.
Variables.
XPos....... X co-ordinate of window
YPos....... Y co-ordinate of window
Width...... Width of window 0-5
Depth...... Depth of window 0-6
ZOOM
ZOOM
Mark Jones takes you up, up and away... with this
instant enlarger for the bleary-eyed Spectrum.
Zoom is an easy to use machine-code utility and allows the
user to enlarge to full screen size the area of the screen
enclosed within a window. This window can be varied in size
from 8-256 pixels wide and from 3-192 pixels high. When in
Magnify mode the magnified area can be viewed continuously
as the window is moved. Since the magnified area can also
itself be magnified, using the same window, infinite magni-
fication is possible, even if of doubtful use. The routine
does not magnify the colour but produces the magnification
in the current permanent attribute colour.
The routine accesses various Basic variables for its
parameters. This means you do not have to bother Poking any
numbers, but just use a Let statement. If you call the
routine without having assigned the following variables a
"2 Variable not found" error will be given.
The machine code has comprehensive error checking. Zoom
will not allow XPos or YPos to be values that make a part
of the window go off screen. If, say, XPos was 270, an
illegal screen co-ordinate, Zoom would give XPos a new
value that ensured that the window was entirely on the
screen. This value would vary with the size of the window.
The width of the window can have values between 0 and 5,
the depth can have values between 0 and 6. If the variables
Width or Depth have values that are too big Zoom will
change the value to the maximum permissible value. Likewise
if either has a negative value Zoom will replace the value
with 0. The width and depth numbers correspond to the
following window sizes:
Width Depth
0 256 pixels 192 pixels
1 128 96
2 64 48
3 32 24
4 16 12
5 8 6
6 - 3
Thus to have a window size 64 pixels by 12 pixels, Width
would be 2 and depth would be 4. If you wish to see an
example of Zoom error correcting, load up Zoom code and
then run the following lines of Basic.
10 LET xpos=260: LET ypos=-10
20 LET width=6: LET depth=-5
Having run the program type
RANDOMIZE USR 50000
This will draw the Zoom window. In this case you will see a
very tall, thin window. If you now type PRINT XPos,YPos,
Width,Depth you will find that Width=5, Depth=0, XPos=248
and YPos=192. Since XPos and YPos denote the top left cor-
ner of the window, YPos has been made 192 since the window
is 192 pixels high, i.e., this is the first value of YPos
above -10 that allows the window to appear/sit on the
screen. XPos has been rounded down until the window is on
the screen, in this case 256-window width.
The algorithm used for Zoom takes each line of the
window, places it in a buffer and keeps on doubling it in
width until it is 32 bytes wide. It then puts the 32-byte
buffer down on the screen - 192/(window y size) - times.
The initial form of the screen is saved at 32768 and the
magnified image is formed on the normal screen, i.e., at
16384. To create Zoom, type in program A and then save it.
Now try running it, if you have no errors, then save the
code. The code can be used independently of program B; this
program is provided to help you use Zoom.
Basic program commands.
A ... Clear main screen and back-up.
B ... Move back-up screen down to current window screen.
L ... Load with new back-up screen.
m ... Magnify area under window until new key press.
M ... Continuously magnify. View can be moved around using
normal direction keys.
N ... Retrieve back-up screen.
P ... Make magnified image current window screen.
s ... Alter window movement step size.
x ... Increase window width.
X ... Decrease window width.
y ... Increase window depth.
Y ... Decrease window depth.
Machine-code routines.
Address
50000 XOR current window onto screen. Doing this twice
will delete the window
50003 Move screen from 32768 to 16384
50011 Move screen from 16384 to 32768
50019 Move screen from 39680 to 16384
50027 Move screen from 16384 to 39680
50039 Magnify area under window
The area 50708-50800 is used as workspace by Zoom and
should be left clear.
32768-39679 Used to store screen during magnification.
39680-46591 Used to store back-up screen.
Variables.
XPos....... X co-ordinate of window
YPos....... Y co-ordinate of window
Width...... Width of window 0-5
Depth...... Depth of window 0-6