| convert |
(Color target, Object value [, Array grid]) |
typedict.Image |
| convert |
(Image value, Array grid) |
|
| |
Converts the pixels in this image that match
target
and are selected by the optional
grid
argument to a color determined by
value,
which must be a
Color,
an
Image,
or
NULL,
and returns this image to the caller.
If
value
is a color all selected pixels are changed to that color.
If
value
is an image each selected pixel is mapped into
value
and the pixel at that location in
value
is used to replace the selected pixel.
Finally, if
value
is
NULL
and this image support alpha, then selected pixels are assigned
an alpha value of
0.0,
which effectively erases them.
The
grid
argument should be an array of four numbers.
The first two specify the width and height (in pixels) of the grid
used to partition this image.
The second two numbers specify the column and row of the only pixel
in each grid that can be selected and converted.
If
convert
is called with an image as the first argument then
grid
must be supplied and every pixel selected by
grid
in this image is converted to the corresponding pixel in
value.
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| Example: |
The program,
import yoix.*.*;
Image img = {
String source = "http://www.yoix.org/imgs/ATTlogo.gif";
double metrics = 1.1;
};
Image img_merged = {
Color background = Color.black;
Array metrics = {0, -1, 0, 0};
Dimension size = {
double width = img.size.width;
double height = img.size.height;
};
};
JFrame f = {
Color background = Color.lightGray;
paint(Rectangle r) {
int n;
graphics { // "named block"
gsave();
rectclip(r);
recterase(r);
moveto(72, 144);
img_merged.source = NULL;
showimage(img);
showimage(img_merged);
for (n = 0; n < 15; n++) {
img_merged.convert(img, new Array{5, 3, n%5, n%3});
showimage(img_merged);
}
setrgbcolor(1, 0, 0);
moveto(36, 144);
lineto(300, 144);
stroke();
grestore();
}
}
};
f.visible = TRUE;
is a fairly complicated example that uses
convert
to merge one image into another in fifteen steps.
Both images have
metrics
entries.
In the first image
metrics
is a double, which means showimage, which is defined in
Graphics,
uses it as the horizontal width.
In the second image we set a vertical side bearing,
which controls the positioning of the image's upper left corner,
but the horizontal and vertical widths are both
0,
because we want to draw it in the same place 16 times.
| | |
| Return: |
Image
| | |
| See Also: |
convolve,
getpixel,
replace,
rescale,
setpixel,
transform
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