How to get the effective area of the picture by vb6?

[xiaoyao]

A PNG image with a transparent channel, for example, where does the left start with pixels and the top start with pixels? Add a border to the active area of the image.

[xiaoyao]

Please help me move to the question area.

[Arnoutdv]

Can you explain what you mean with where does the left and top start?
An image is a rectangle with a height and a width, in pixels.
So 0,0 is the top left.

[xiaoyao]

Can you explain what you mean with where does the left and top start?
An image is a rectangle with a height and a width, in pixels.
So 0,0 is the top left.

I converted the image from the SVG component to the transparent PNG format. But there are a lot of blanks (transparent) around, so you need to get a non-blank area, just like a screenshot, you need to know which area to cut.

For example, for a 300*500 pixel picture, only the middle 245*380 area is actually non-transparent.
If you want to analyze the ARGB format of PNG, is there any algorithm to quickly obtain the middle area, and finally copy this image to other controls for display, or save a new PNG image