I have an app icon for iOS but Apple doesn't allow alpha to be in the image. How to remove this alpha channel? I only have the png image with me I don't have the source file as my friend did the image for me.
我有一个iOS的app图标，但是苹果不允许alpha出现在图片中。如何移除这个alpha通道?我只有png图像，我没有源文件，因为我的朋友为我做了图像。
9 个解决方案
#1
26
Assuming you don't have another image editor, then you can open it in Preview on your Mac, and use the Export option to resave it in a different format- to ensure you get rid of the alpha channel, it might be best to export to JPG (best quality), then open that and export it as a PNG again.
假设你没有另一个图像编辑器,你可以打开它在你的Mac预览,并使用导出选项重新保存在不同的格式——确保你摆脱alpha通道,最好向JPG出口(质量),然后打开,并将其导出为一个PNG。
Having said that, I suspect you're probably OK submitting an icon with a transparency channel as long as there's no actual transparency.
说了这么多，我想只要没有实际的透明度，你就可以用透明通道提交一个图标。
#2
99
The accepted answer to export to JPG, then back to PNG is not recommended.
不建议导出到JPG，然后返回到PNG。
- It's an extra step in the process (2 exports)
- 这是过程中的一个额外步骤(2导出)
- JPG is lossy, so you will lose some image data
- JPG是有损的，所以会丢失一些图像数据
Here's a super fast and easy way to do this without the extra export or saving to (lossy) JPG:
这里有一个超级快速和简单的方法，不需要额外的导出或保存到(有损)JPG:
Using Preview app (Mac):
使用预览应用程序(Mac):
- Open the image
- 打开图片
- Command-Shift-S to Duplicate (creates a copy)
- 复制命令移位- s(创建副本)
- Command-S to Save
- 命令来保存
- Deselect the "Alpha" checkbox
- 取消选择“阿尔法”复选框
-
Delete " copy" from filename (including the space)
- This will overwrite your original, if you want to keep the original, just leave "copy" in the name
- 这将覆盖您的原件，如果您想保留原件，只需在名称中保留“copy”即可
- 从文件名中删除“copy”(包括空格)这将覆盖您的原始文件，如果您想保留原始文件，只需在名称中保留“copy”即可
- Save
- 保存
-
Click 'Replace' to confirm you want to overwrite the original
- Only necessary if you are overwriting your original
- 只有当你重写你的原作时才有必要
- 单击“替换”以确认您只在重写原始代码时需要重写原始代码
#3
26
If you are using the Preview app, there's no need to export then re-export between jpg and png, just choose export and below the filetype (PNG) you will see an alpha checkbox, unset it and save.
如果您使用的是预览应用程序，则无需导出，然后在jpg和png之间进行再导出，只需选择导出，然后在filetype (png)下面，您将看到一个alpha复选框，取消设置并保存。
#4
9
There's no need to export the image to jpg first. You can uncheck the checkbox for the alpha channel and export directly from a png to a png without alpha channel in the preview app.
不需要先将图片导出到jpg。您可以取消选中alpha通道的复选框，并在预览应用程序中直接从png导出到png，而没有alpha通道。
#5
8
You can try imagemagick (also easily resize for different sizes):
您可以尝试imagemagick(也很容易调整大小):
convert in.png -background black -alpha remove -alpha off -resize 1024x1024 out.png
#6
3
Just got the the following error when trying to upload my app to the iTunes app store:
刚刚在尝试上传我的app到iTunes app store时出现以下错误:
iTunes Store Operations Failed
iTunes商店操作失败
ERROR ITMS-90717: "Invalid App Store Icon. The App Store icon in the asset catalog in 'MyApp.app' can't be transparent nor contain an alpha channel."
错误ITMS-90717:“应用商店图标无效。”App Store图标在“MyApp”的资产目录中。app不能透明也不能包含alpha通道
I confirmed that my app store icons did include the alpha channel by locating the asset in Finder and looking up its info (⌘+i). Underneath More info, it showed:
我证实我的应用程序商店图标包括阿尔法通道通过定位在Finder中资产并查找其信息(⌘+ I)。在更多的信息下面，它显示:
Alpha channel: Yes
阿尔法通道:是的
Found the solution above to use Preview to remove the alpha channel by exporting it with the Alpha checkbox unchecked, but figured a way to batch export them since I had 18 assets I needed to strip the alpha channel from.
找到上面的解决方案，使用预览来删除alpha通道，通过对alpha复选框进行无限制的导出，但是我找到了一种方法来批量导出它们，因为我有18个资产，我需要去掉alpha通道。
The way I got batch exporting to work was to select all my app icon assets in finder > right click > open (or open with preview)
批量导出的方法是在finder >中选择我的app图标资产右键点击>打开(或打开预览)
All of the assets will now appear in the same window. Select all (⌘+a), and then select File > Export Selected Images… > Expand Options > uncheck the Alpha checkbox > Choose (your destination folder)
所有的资产现在都将出现在同一个窗口中。选择所有(⌘+一个),然后选择文件>导出所选图片…>扩展选项> >取消阿尔法复选框选择(你的目标文件夹)
Done! All your images are now exported with the alpha channel stripped off.
完成了!现在，您的所有映像都被导出，去掉了alpha通道。
#7
3
To remove alpha channel from png:
从png中移除alpha通道:
on Mac: Preview version 9.0 (macOS Sierra) can remove the alpha channel if you export or save the image.
在Mac上:预览版9.0 (macOS Sierra)可以删除alpha通道，如果您导出或保存图像。
Preview version 10.0 (944.2) (macOS High Sierra) does not remove the alpha channel. Both Export and/or Save does not remove the alpha channel from the image.
预览版10.0 (944.2)(macOS High Sierra)没有删除alpha通道。导出和/或保存都不会从映像中删除alpha通道。
#8
0
the alpha check box is no longer there in preview
alpha复选框不在预览中
#9
0
Well, since you're on a Mac, next time you probably just want to use Automator. Convert the image to BMP (lossless) and back to PNG. Let it save and voila...
既然你用的是Mac，下次你可能只想用Automator。将图像转换为BMP(无损)并返回到PNG。让它保存，然后……
#1
26
Assuming you don't have another image editor, then you can open it in Preview on your Mac, and use the Export option to resave it in a different format- to ensure you get rid of the alpha channel, it might be best to export to JPG (best quality), then open that and export it as a PNG again.
假设你没有另一个图像编辑器,你可以打开它在你的Mac预览,并使用导出选项重新保存在不同的格式——确保你摆脱alpha通道,最好向JPG出口(质量),然后打开,并将其导出为一个PNG。
Having said that, I suspect you're probably OK submitting an icon with a transparency channel as long as there's no actual transparency.
说了这么多，我想只要没有实际的透明度，你就可以用透明通道提交一个图标。
#2
99
The accepted answer to export to JPG, then back to PNG is not recommended.
不建议导出到JPG，然后返回到PNG。
- It's an extra step in the process (2 exports)
- 这是过程中的一个额外步骤(2导出)
- JPG is lossy, so you will lose some image data
- JPG是有损的，所以会丢失一些图像数据
Here's a super fast and easy way to do this without the extra export or saving to (lossy) JPG:
这里有一个超级快速和简单的方法，不需要额外的导出或保存到(有损)JPG:
Using Preview app (Mac):
使用预览应用程序(Mac):
- Open the image
- 打开图片
- Command-Shift-S to Duplicate (creates a copy)
- 复制命令移位- s(创建副本)
- Command-S to Save
- 命令来保存
- Deselect the "Alpha" checkbox
- 取消选择“阿尔法”复选框
-
Delete " copy" from filename (including the space)
- This will overwrite your original, if you want to keep the original, just leave "copy" in the name
- 这将覆盖您的原件，如果您想保留原件，只需在名称中保留“copy”即可
- 从文件名中删除“copy”(包括空格)这将覆盖您的原始文件，如果您想保留原始文件，只需在名称中保留“copy”即可
- Save
- 保存
-
Click 'Replace' to confirm you want to overwrite the original
- Only necessary if you are overwriting your original
- 只有当你重写你的原作时才有必要
- 单击“替换”以确认您只在重写原始代码时需要重写原始代码
#3
26
If you are using the Preview app, there's no need to export then re-export between jpg and png, just choose export and below the filetype (PNG) you will see an alpha checkbox, unset it and save.
如果您使用的是预览应用程序，则无需导出，然后在jpg和png之间进行再导出，只需选择导出，然后在filetype (png)下面，您将看到一个alpha复选框，取消设置并保存。
#4
9
There's no need to export the image to jpg first. You can uncheck the checkbox for the alpha channel and export directly from a png to a png without alpha channel in the preview app.
不需要先将图片导出到jpg。您可以取消选中alpha通道的复选框，并在预览应用程序中直接从png导出到png，而没有alpha通道。
#5
8
You can try imagemagick (also easily resize for different sizes):
您可以尝试imagemagick(也很容易调整大小):
convert in.png -background black -alpha remove -alpha off -resize 1024x1024 out.png
#6
3
Just got the the following error when trying to upload my app to the iTunes app store:
刚刚在尝试上传我的app到iTunes app store时出现以下错误:
iTunes Store Operations Failed
iTunes商店操作失败
ERROR ITMS-90717: "Invalid App Store Icon. The App Store icon in the asset catalog in 'MyApp.app' can't be transparent nor contain an alpha channel."
错误ITMS-90717:“应用商店图标无效。”App Store图标在“MyApp”的资产目录中。app不能透明也不能包含alpha通道
I confirmed that my app store icons did include the alpha channel by locating the asset in Finder and looking up its info (⌘+i). Underneath More info, it showed:
我证实我的应用程序商店图标包括阿尔法通道通过定位在Finder中资产并查找其信息(⌘+ I)。在更多的信息下面，它显示:
Alpha channel: Yes
阿尔法通道:是的
Found the solution above to use Preview to remove the alpha channel by exporting it with the Alpha checkbox unchecked, but figured a way to batch export them since I had 18 assets I needed to strip the alpha channel from.
找到上面的解决方案，使用预览来删除alpha通道，通过对alpha复选框进行无限制的导出，但是我找到了一种方法来批量导出它们，因为我有18个资产，我需要去掉alpha通道。
The way I got batch exporting to work was to select all my app icon assets in finder > right click > open (or open with preview)
批量导出的方法是在finder >中选择我的app图标资产右键点击>打开(或打开预览)
All of the assets will now appear in the same window. Select all (⌘+a), and then select File > Export Selected Images… > Expand Options > uncheck the Alpha checkbox > Choose (your destination folder)
所有的资产现在都将出现在同一个窗口中。选择所有(⌘+一个),然后选择文件>导出所选图片…>扩展选项> >取消阿尔法复选框选择(你的目标文件夹)
Done! All your images are now exported with the alpha channel stripped off.
完成了!现在，您的所有映像都被导出，去掉了alpha通道。
#7
3
To remove alpha channel from png:
从png中移除alpha通道:
on Mac: Preview version 9.0 (macOS Sierra) can remove the alpha channel if you export or save the image.
在Mac上:预览版9.0 (macOS Sierra)可以删除alpha通道，如果您导出或保存图像。
Preview version 10.0 (944.2) (macOS High Sierra) does not remove the alpha channel. Both Export and/or Save does not remove the alpha channel from the image.
预览版10.0 (944.2)(macOS High Sierra)没有删除alpha通道。导出和/或保存都不会从映像中删除alpha通道。
#8
0
the alpha check box is no longer there in preview
alpha复选框不在预览中
#9
0
Well, since you're on a Mac, next time you probably just want to use Automator. Convert the image to BMP (lossless) and back to PNG. Let it save and voila...
既然你用的是Mac，下次你可能只想用Automator。将图像转换为BMP(无损)并返回到PNG。让它保存，然后……