Creating a gambas2 program, step by step, a telephone index
From : http://listingambas.blogspot.com/2011/06/anexo-2-convert-miniaturas-en-nuestro.html
... ...
From : http://listingambas.blogspot.com/2011/06/anexo-2-convert-miniaturas-en-nuestro.html
Annex 2: convert, thumbnails in our gridViewData
In
our gridviewData, we see that we can' t display the whole
pictures. How about making small thumbnails of them that we
may see better ... .????
Linux has commands and free programs to do so .... Let's work:
Linux has commands and free programs to do so .... Let's work:
The
program
convert
help us to reduce the required size images uploaded to our gridviews,
Installation:
From
the console prompt, type "convert". If it can't be found, it would
install the program:
$
Convert
The
program "convert" can be found in the following packages:
*
Imagemagick
*
Graphicsmagick-imagemagick-compat
Try:
sudo apt-get install <paquete selected>
bash:
convert: command not found
$
Sudo apt-get install imagemagick
We
are asked to confirm installation of the package, and it
install itself.
Use of convert in our program: the SHELL command
Once the program
installed , we include the code to do:
-
every time you enter or edit a record, at time of filling the gridviewData, we want to display a thumbnail (eg 120x120 pixels) in our gridviewsdata, instead of the selected image.
-
to "resize" an image to 120x120 from the command line, we would do as follows
$
Convert-size 120x120-resize 120x120 + lena512.bmp profile '*' thumbnailDD.jpg
d
" Thus, "-size 120x120" gives a hint to the JPEG decoder that the image will be downscaled to 120x120, allowing it to run faster, preventing it to
return a high-resolution image. The
"-resize 120x120" specifies the desired dimensions of the output image.
It will be scaled so its largest dimension is
120 pixiles. The "*" in "+ profile" removes
any ICM, EXIF, IPTC, or other profiles iformation that may be held in
the input and ise not desired in the thumbnails. "
Running
the image "lena512.bmp" need 257.1 kib; we coverted
it to the so called "thumbnailDD.jpg" of only 3.7 kib.
Well,
and as we code it in gambas2, we use the command "SHELL".
We
will create a new module called thumbnails,
and put in it this code:
public
function DoIt
(file
AS
String
, size
AS
String
) AS
string
DIM
Proc
AS
process
DIM sline
AS
String
DIM
mini
AS
String
'Check if Exist a directory named mini
IF
Exist (
"
~
/
listin
/
mini
"
) THEN
' directory
mini Exists,
no
need
to
create
ELSE
' directory
mini does
not exists, we must create it ...
Mkdir " ~
/
listin "
'And
then "
mini
"
Mkdir " ~
/
listin /
mini "
ENDIF
'Note:
'Command:
file.dir
(path),
extract
only
the path name (without file name)
'Command:
file.name
(path), extract
only the
file name (without path)
mini
=
"
~
/
listin
/
mini
"
&
"/
mini"
&
file
. name
( file
)
IF
Exist (
mini
)
Then
' file
miniExists
, do
not have to create it
RETURN
mini
ELSE
'Size
can
be
120x120,
96x96,
etc.
line
= " convert
-size " & size &
"" & file &
"-resize" & size &
"+ profile
'*'" & mini
proc
= SHELL
line WAIT
'Execute
the process and control the output
flow of
your application
return
mini
ENDIF
END
Notes:
1 - The
function Thumnais.DoIt
()
in
addition to resizing the image returns the path
where it is created.
2 - "
~
/
l
": the
character ~ is
replaced by the user's home directory, regardless of which user it is
"/ home / July" or "/ home / john".
3
- Exist
()
: If does not
Exists ( "
~
/
listin
/
mini
"
), we
create a directory
called listin / mini from
our home / user, where we store all the thumbnails made. If file exists, we will not run convert
4. SHELL
, this
command runs from the command line the program convert with all
the attributes that we added (file path, size, and new name for
the thumbnail)
Well,
once developed the code and created the new module, we will create a checkbox
(checkboxmini) in the form Fmain
providing the user to "check or uncheck" the option use of thumbnails in gridviewData , and
thus we also modify subroutine "title.fill ()"
to display the thumbnails rather than original files.
In Fmain form, we
need
to code
that when the value of checkboxmini changes, we also have to run the
subroutine Title.Fill
()
PUBLIC
SUB
CheckBoxmini_Click ()
Title. Fill
()
END
And
in the code Title.Fill
()
:
PUBLIC
SUB Fill ()
DIM
a AS
Integer
FMain.
GridViewData . Rows . COUNT
= var. id . COUNT
FOR a =
0 TO var. id . COUNT
- 1
WITH
FMain
IF
FMain.
CheckBoxmini
. Value
=
FALSE
THEN
.
GridViewData . Row
s . height
= 25
.
GridViewData [a, 0 ]. Picture
=
Picture [var.
picture [a]]
ELSE
.
GridViewData [a, 0 ]. Alignment
= 1
.
GridViewData . Row
s . height
= 100
.
GridViewData [a, 0 ]. Picture
=
Picture [Thumbnail.
DoIt (var. photo [a], "96x96" )]
ENDIF
.
GridViewData [a, 1 ]. text
= var. name [a]
.
GridViewData [a, 2 ]. text
= var. surname [a]
... ...
Note:
The yellow part is what we changed. It make that
when checkboxmini.value = false the normal picture is drawn, and when it is True, the thumbnail
is produced and the row height is sized to display it.
Important
Note: We add the same code at
any
location
where gridviewData
is filled .
And in filter
module ,
we
must
make
the same changes
to .ConceptFilter:
... ...
valid
=
in (sLine, pattern) AND
in (sLine, pattern1) AND in (sLine,
pattern2)
IF
valid THEN
count +
=
1
FMain. GridViewData
. Rows
. COUNT
=
count
WITH
FMain
IF
FMain. CheckBoxmini
. Value
=
FALSE
THEN
. GridViewData
. Rows
. height
=
25
. GridViewData
[count -
1
, 0
]. Picture
=
Picture [var. picture
[a]]
ELSE
. GridViewData
[count -
1
, 0
]. Alignment
=
1
. GridViewData
. Rows
. height
=
100
. GridViewData
[count -
1
, 0
]. Picture
=
Picture [thumbnails. doIt
(var. photo
[a], "96x96"
)]
ENDIF
.GridViewData
[count -
1
, 1
]. text
=
var. name
[a]
... ...
Here is an example
of records with and without thumbnails:
|
No
thumbnails
|
With
thumbnails
|
 |
 |
 .... much
better with thumbnails, isn't it? |