z*y
发帖数: 1311 | 1 想在Storyboard里修改TabBarItem的image
总是不行，画面是灰色一片（红圈部分）
image本身不大（24X24）
谢谢指点 | f*******n
发帖数: 12623 | 2 https://developer.apple.com/library/ios/#DOCUMENTATION/UIKit/Reference/
UITabBarItem_Class/Reference/Reference.html#//apple_ref/occ/instm/
UITabBarItem/initWithTitle:image:tag:
"The alpha values in the source image are used to create the unselected and
selected images—opaque values are ignored." | z*y
发帖数: 1311 | 3
and
Thanks. But my images do not contain alpha value.
【在 f*******n 的大作中提到】
: https://developer.apple.com/library/ios/#DOCUMENTATION/UIKit/Reference/
: UITabBarItem_Class/Reference/Reference.html#//apple_ref/occ/instm/
: UITabBarItem/initWithTitle:image:tag:
: "The alpha values in the source image are used to create the unselected and
: selected images—opaque values are ignored."
| f*******n
发帖数: 12623 | 4 Every pixel in a PNG image has an RGBA (red, green, blue, alpha) value.
Alpha controls the transparency of that pixel. In a "normal" (opaque) image,
every pixel has alpha = 1 (not transparent at all).
Tab bar icons do not care about the RGB parts; only the Alpha. Alpha = 0
means transparent; alpha = 1 means white (when unselected) or blue (when
selected). You can only control the range in between (it's basically like a
"grayscale" image, except in alpha channel instead of RGB). You don't have
control over the colors other than black, white, or gray.
So basically, what you have to do is first make a grayscale (black and white
) image, and then set those black/white values in the alpha channel instead
of in the RGB (RGB will be ignored).
【在 z*y 的大作中提到】
:
: and
: Thanks. But my images do not contain alpha value.
| z*y
发帖数: 1311 | 5 got it, thank you.
try some website that converts to alpha, works!
image,
a
white
instead
【在 f*******n 的大作中提到】
: Every pixel in a PNG image has an RGBA (red, green, blue, alpha) value.
: Alpha controls the transparency of that pixel. In a "normal" (opaque) image,
: every pixel has alpha = 1 (not transparent at all).
: Tab bar icons do not care about the RGB parts; only the Alpha. Alpha = 0
: means transparent; alpha = 1 means white (when unselected) or blue (when
: selected). You can only control the range in between (it's basically like a
: "grayscale" image, except in alpha channel instead of RGB). You don't have
: control over the colors other than black, white, or gray.
: So basically, what you have to do is first make a grayscale (black and white
: ) image, and then set those black/white values in the alpha channel instead
| z*y
发帖数: 1311 | 6 想在Storyboard里修改TabBarItem的image
总是不行，画面是灰色一片（红圈部分）
image本身不大（24X24）
谢谢指点 | f*******n
发帖数: 12623 | 7 https://developer.apple.com/library/ios/#DOCUMENTATION/UIKit/Reference/
UITabBarItem_Class/Reference/Reference.html#//apple_ref/occ/instm/
UITabBarItem/initWithTitle:image:tag:
"The alpha values in the source image are used to create the unselected and
selected images—opaque values are ignored." | z*y
发帖数: 1311 | 8
and
Thanks. But my images do not contain alpha value.
【在 f*******n 的大作中提到】
: https://developer.apple.com/library/ios/#DOCUMENTATION/UIKit/Reference/
: UITabBarItem_Class/Reference/Reference.html#//apple_ref/occ/instm/
: UITabBarItem/initWithTitle:image:tag:
: "The alpha values in the source image are used to create the unselected and
: selected images—opaque values are ignored."
| f*******n
发帖数: 12623 | 9 Every pixel in a PNG image has an RGBA (red, green, blue, alpha) value.
Alpha controls the transparency of that pixel. In a "normal" (opaque) image,
every pixel has alpha = 1 (not transparent at all).
Tab bar icons do not care about the RGB parts; only the Alpha. Alpha = 0
means transparent; alpha = 1 means white (when unselected) or blue (when
selected). You can only control the range in between (it's basically like a
"grayscale" image, except in alpha channel instead of RGB). You don't have
control over the colors other than black, white, or gray.
So basically, what you have to do is first make a grayscale (black and white
) image, and then set those black/white values in the alpha channel instead
of in the RGB (RGB will be ignored).
【在 z*y 的大作中提到】
:
: and
: Thanks. But my images do not contain alpha value.
| z*y
发帖数: 1311 | 10 got it, thank you.
try some website that converts to alpha, works!
image,
a
white
instead
【在 f*******n 的大作中提到】
: Every pixel in a PNG image has an RGBA (red, green, blue, alpha) value.
: Alpha controls the transparency of that pixel. In a "normal" (opaque) image,
: every pixel has alpha = 1 (not transparent at all).
: Tab bar icons do not care about the RGB parts; only the Alpha. Alpha = 0
: means transparent; alpha = 1 means white (when unselected) or blue (when
: selected). You can only control the range in between (it's basically like a
: "grayscale" image, except in alpha channel instead of RGB). You don't have
: control over the colors other than black, white, or gray.
: So basically, what you have to do is first make a grayscale (black and white
: ) image, and then set those black/white values in the alpha channel instead
| e***t
发帖数: 78 | 11 请问您在哪个网站转的？谢谢！
【在 z*y 的大作中提到】
: got it, thank you.
: try some website that converts to alpha, works!
:
: image,
: a
: white
: instead
|
|
