I am dealing with a game texture. The alpha channel determines the smoothness.
I would like to paint the alpha channel (make it opaque or transparent) in GIMP.
I have clicked the alpha channel in the Layer tab.
When I select a brush, select White and paint, the checkerboard shows up more:
However, when I paint with Black to make the alpha channel opaque, nothing happens.
What am I doing wrong?
Thank you.
Yes, you are doing it wrong. When you enable/disable a channel in the Channels tab, you make it sensitive to paint operation. But when you paint with the brush on a transparent area the value of the alpha channel is always 100% (or more accurately the opacity of the brush).
If you want to paint the alpha-channel, you have to use "layer masks":
Layer > Mask > Add layer mask to add a mask (in you cae you probably want to initialize with "Transfer layer's alpha channel"
On the status bar at the bottom if the image, the layer name is now "{name of layer} mask"
You also have a thumbnail of the mask newt to the layer thumbnail in the Layers list.
Paint on the mask (black is transparent, white is opaque)
You can switch from painting RGB or Alpha channelby clicking the layer or mask thumbnail in the Layers list.
Possibly Layer > Mask > Apply layer mask when done (but you should be able to export the image directly, this will apply the mask)
Related
In GIMP version 2.8, I have an image with a black foreground, and a transparent background. I want to set the entire foreground to red, instead of black. What's the simplest way of doing this?
I have tried using the fuzzy select tool and doing a bucket fill on the selection, but this doesn't seem to select the entire foreground. After the bucket fill, there is still a black line around the edge of the foreground image. So it seems that the fuzzy selector didn't select the entire foreground. On closer inspection, the edges of the foreground are not perfectly black, but have some grey pixels. But when using the fuzzy selection, I set a very high threshold (250), so I would have thought this this would select the entire foreground, including the grey pixels.
Any help? Thanks!
The gray pixels aren't grey, they are partially transparent black pixels. If you replace black, you want to keep that partial transparency because this is what gives smooth edges. And there is an easy solution:
Set the alpha-lock of the layer (this is the checkerboard icon at the top of the Layers list) (or in code: gimp-layer-set-lock-alpha)
Do not use selection.
Bucket-fill the layer with the required color. The alpha-lock will preserve the opacity of the pixels.
Currently I'm working on a simple image editor where you can with a brush alter the alpha channel.
My problem is, when a UIImageView with 0 or near zero alpha image is presented on another UIView, that has a dark color (like brown, black, etc), a strange composition appears. Image becomes visible like its alpha has never been changed. When the back UIView is white, everything is normal.
You'll want to say "keep it white" but I'm currently using this UIView as the background canvas and user has the ability to change the color.
The captures I took are from Reveal, but the appearance is exactly the same on device as well. Here is what I mean with all this talk:
This is an image with 20% alpha set to all it's pixels. The image looks ok. From Reveal, I can see that the image has the correct alpha channel. Everyting is as it should be.
Here is the same image with 15% alpha on a darker blue background (sorry, while capturing I changed the alpha). From Reveal, everything is again looking normal.
But when you look at the device, this is what you see. This is the same UIImage with 15% alpha set to all pixels and presented in UIImageView.
The image is fully appearing on the background dark blue UIView, like its alpha is not 15%. Changing alpha when working on a dark background has not much effect. It simply adds blue all over, or 100% alpha returns to the original image. Even when setting the alpha of all pixels to 0, the image is clearly visible.
Is there something I'm missing? Why this composition (or blending of two UIView objects) error/bug/problem appearing? Is there a value that I am forgetting to set? Or is this normal and am I doing something wrong?
How can I get rid of the white layer drawn under the bitmap images by Delphi/Windows when Glyph property of TBitBtn is used. I just want to draw the image, no shadow under it, no other layers that comes automatically. I am inserting round shaped 24 bit bitmap images.
Since you have a 24-bit bitmap, there is no alpha transparency, so Delphi uses the bottom left pixel of the image to determine the transparent color. All pixels with that color are treated as transparent. The part of the image with the shadow effect is not an exact match for the designated transparent color, so those pixels are painted normally, just like the rest of the image.
The shadow appears white because there was a white background in the graphic program when your designer applied the shadow effect.
Either edit the image to remove the shadow, or use a 32-bit image with alpha transparency. You'll be hard-pressed to apply alpha transparency after the fact. Fix the source image.
My base image is a complex shape with multiple colors and an alpha background.
My shimmer effect is a white slanted gradient with an alpha background.
My goal is to animate the shimmer image over top of the base image, but make the alpha values of of the shimmer match those of the base image.
I've only used layer masks to hide areas based on the color, not to both show AND hide parts of an image. Will I need to create multiple masks to achieve this? A white version of my base image that will show through the masked shimmer image, all on top of my colored base image?
Since your shimmer effect is created by moving a single image/layer over a base image, you only need one mask in the shape of the non-alpha values in your base image. You will likely need to use a container view for your shimmer image view/layer that you overlay onto of the base image, then set the image mask on the container.
I have an old app (Delphi 5) which I want to give it some changes.
I have set a Glyph.Data for a speedbutton, but some colors are transparent and in some places I see small white dots on my image, I do not want to set transparency for the image, How to remove it (transparency)?
Any help is really appreciated.
Thanks :)
The transparency is a color that is not drawn.
You just have to change the image or set another color as the transparent one.
From Delphi 6 Help
Transparent color
Use the Transparent color drop-down to
specify which color is used to create
a mask for drawing the image
transparently. The default transparent
color is the color of the bitmap's
left-most pixel in the bottom line.
You can also change the transparent
color by clicking directly on a pixel
in the selected image.
When an image has a transparent color,
any pixels in the image of that color
are not rendered in that color, but
instead appear transparent, allowing
whatever is behind the image to show
through.
If the image is an icon, Transparent
color appears grayed and the
transparent color is set to clNone.
This is because icons are already
masked.
Set TSpeedButton.Transparent to False.
I have found the answer, Delphi thinks the transparent color is the color of most left - bottom pixel of this image. So If I set a color which is not used in my image in the most left-bottom of my image, then Delphi only will make that small pixel transparent and other parts of my image will be OK without transparency, So this post is completed by myself :))