Please help regarding ZOOM

[wizards]

Hello All,

I am new to ImageMagick and doing a small application using VC++.
I have a problem with zoom. i have different sizes of images like 2048X1556, 1828X778 etc.
I have to zoom at a time a min of 3 images, the zooming factor is double to the size of the image.
If I zoom by double the size of the image size then it is taking too much time to zoom all 3 images.

It's very argent to me, plz help me.
Can you please help me how to reduce the time to zoom.

Thanks In advance.
Wizards

[wizards]

Hello All,

I gained speed by using "scale" method instead of "Zoom".
Please may i know what is the difference between "scale" and "zoom"?

Can i use threads to increase more speed?

Thanks In Advance
Wizards.

[anthony]

Zoom is another name for resize, and was in fact the original name of the program by Paul Heckbert whcih became the diffinitive image resizing method used by ALL modern day orthogonal resizing programs.

You can even still download that program!
http://www.xmission.com/~legalize/zoom.html

Resize itself does a fill 2 pass filtered (weighted color averaging) resizing of the image to get the colors exactly right.

Scale just does color merging (on shrink) and duplication on enlarge, so is faster.

Sample is the same, but does row/column removal on shrink.

see IM examples, resizing Images for all the details
http://www.imagemagick.org/Usage/resize/#filter

[wizards]

Thank you very much sir,

but i have a doubt that the scale will reduce quality of image.
Suppose if quality reduces which filter is better for me (Speed should not reduce).

Thanks in advance

[anthony]

The default resize filter is very good. It will pick it depending on the type of image for best results.