Doc #70802 [Opn]: Confusing alpha values in help

Edit report at https://bugs.php.net/bug.php?id=70802&edit=1 ID: 70802 Updated by: cmb@php.net Reported by: chris at ocproducts dot com Summary: Confusing alpha values in help Status: Open Type: Documentation Problem Package: GD related PHP Version: Irrelevant Block user comment: N Private report: N New Comment: Related to bug #67900. Previous Comments: ------------------------------------------------------------------------ [2015-10-27 16:20:24] chris at ocproducts dot com Description: ------------ --- From manual page: http://www.php.net/function.imagecolorat --- The imagecolorsforindex example embedded within the imagecolorat documentation shows output with alpha of 127. PHP alpha is inverted from what people normally expect, so people will think 127 is either fully opaque or 50% opaque (depending how knowledgable they are). In-fact, 127 is 0% opaque, i.e. 100% transparent. The user is very likely to be confused/misled, as: a) an example showing a fully transparent pixel is not what they'd assume b) it is not otherwise mentioned that this example if of a transparent pixel c) as the RGB components have actual values, a typical user is really going to not expect this, as they don't imagine transparent pixels with RGB values (again, a typical user, not an expert) If you look at the example on the imagecolorsforindex function page it uses a more normal example. I suggest the imagecolorat be given an alpha example with 0. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=70802&edit=1