I am having some trouble with my World of Warcraft addon. Whenever I display my TGA files in the addon, there is a thin white frame around them. The same happens when I convert them to BLPs.
When I look at the images themselves with Preview, there's no white frame, but WoW decides to display one.
How do I resolve this?
I'm guessing you are using TGA files with an alpha channel and the "thin white frame" is about a pixel or less.
This is usually the effect of a matte that is placed under the opaque edges of the artwork prior to calculating the alpha channel. The solution is to generate your own alpha channel and feather the edges in by a pixel or so thus masking the matte.
The explanation is actually a tad more complex than this, but the method works.
Related
I want to make exact 1-pixel thick line without distortions. (means not appeared as 2-pixel lines or 1.5-pixel lines, etc) Because it seems like the Canvas just can't stand Pixel Perfect at times.
It is also depends on CanvasScaler setting, make sure that screen/canvas output is exactly at scale 1x.
Confirm that canvas final scale is all 1x
Also confirm that your displaying game window has 1x scale so that 1 pixel show up nicely too!
(View full unscaled image in another window if sprite in above image appear jagged)
For canvas scaler setting, if you use it in other mode such as "Scale with screen size", and its reference resolution did not match current game window, it will result in non 1x scaling.
If scale is non uniform, jagged or blurry line will start to appear on canvas.
Notice the middle sword sprite.
Canvas' pixel perfect tick box helped nothing so far.
Actually, sorry. Canvases try to respect screen pixels when scaling with PixelPerfect set to true.
The solution was pretty easy - just setting PixelPerfect to false. I got so used to set it to true (because of the UI style I was going for before) that I didn't even consider turning it off. I guess that's mainly due to its name - Pixel Perfect.
xD
I'm having some troubles right now with isometric pixel art. So I'm drawing this picture that is going to be uploaded later in the game, but when I save it and zoom it looks like this:
The picture became blurred and colors are not that bright. Is there anything I could do about it? How can I save it so it will be the same as in the photoshop (300% zoom)?
Would be really grateful for any help.
As Phlume said, you can use Vector base software like illustrator, CorelDraw, Inkscape (freeware) etc. and export it as a SVG image.
OR
for a quick fix, in a Photoshop you can create image in a 300% size (canvas size 3 times then require ) and export image in 96dpi. And further to reduce the image size for faster loading you can try https://tinypng.com/
And by the coding you can resize it to required size.
Photoshop is a raster based program. To retain the clarity of the pixel artwork you should switch to a vector bed program such as illustrator. When you zoom in with illustrator the math recalculate to form clean lines from point to point. The blurry you see in photoshop is a product of the pixel data becoming compressed upon saving and finding a "happy medium" to represent the color within that region.
I need to convert an image to greyscale except for a single color. For example, if there is some red in the image (like a red bus), this will remain in color, but the rest of the image will remain in black & white.
I think I should be able to do a rudimentary job of this by going over each pixel individually, such as here: http://brandontreb.com/image-manipulation-retrieving-and-updating-pixel-values-for-a-uiimage . I am assuming I would just leave certain pixels alone if their red component was above a certain amount, and green/blue was below a certain amount. Otherwise, set the pixel to grayscale. Is this a good approach?
I'm more interested in whether or not it is possible to do to the live camera input, such as with a Core Image filter, or using GPUImage, but I haven't been able to find any suitable filters. Any suggestions?
Update:
This seems to be possible using GPUImage with a GPUImageLookupFilter, as per: https://stackoverflow.com/a/19340583/334982
I've created a lookup.png file in Photoshop, by dropping the Saturation for all colours except red to 0. This works ok, but it doesn't seem to grey out all colours. For example, my skin still looks fairly skin coloured, and my brown table is still fairly brown.
I am doing my iPhone graphics using OpenGL. In one of my projects, I need to use an image, which I need to use as a texture in OpenGL. The .png image is 512 * 512 in size, its background is transparent, and the image has a thick blue line in its center.
When I apply my image to a polygon in OpenGL, the texture appears as if the transparent part in the image is black and the thick blue line is seen as itself. In order to remove the black part, I used blending:
glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
Then my black part of the texture in the polygon is removed. Now only the blue band is seen. Thus the problem is solved.
But I want to add many such images and make many objects in OpenGL. I am able to do that, but the frame rate is very low when I add more and more images to objects. But when I comment out blending, the frame rate is normal, but the images are not seen.
Since I do not have good fps, the graphics are a bit slow and I get a shaky effect.
So:
1) Is there any other method than blending to solve my problem?
2) How can I improve the frame rate of my OpenGL app? What all steps need to be taken in order to implement my graphics properly?
If you want to have transparent parts of an object, the only way is to blend to pixel data for the triangle with what is currently in the buffer (what you are currently doing). Normally, when using solid textures, the new pixel data for a triangle just overwrites what ever was in buffer (as long as it is closers, ie z-buffer). But with transparency, it has start looking at the transparency of that part of the texture, look at what is behind it, all the way back to something solid. Then has combine all of those over lapping layers of transparent stuff till you get the final image.
If all you are wanting your transparency for is something like a simple tree sprite, and removing the 'stuff' form the sides of the trunk etc. Then you may be better of providing more complex geometry that actually defines the shape of the trunk and thus not need to bother with transparency.
Sadly, I don't think there is much you can do to try to speed up your FPS, other then cut down the amount of transparency you are calculating. Maybe even adding some optimization that checks images to see if it can turn of alpha blending for this image or not. Depending on how much you are trying to push through, may save time in the long wrong.
Using images of articles of clothing taken against a consistent background, I would like to make all pixels in the image transparent except for the clothing. What is the best way to go about this? I have researched the algorithms that are common for this and the open source library opencv. Aside from rolling my own or using opencv is there an easy way to do this? I am open to any language or platform.
Thanks
If your background is consistend in an image but inconsistent across images it could get tricky, but here is what I would do:
Separate the image into some intensity/colour form such as YUV or Lab.
Make a histogram over the colour part. Find the most occuring colour, this is (most likely) your background (update) maybe a better trick here would be to find the most occuring colour of all pixels within one or two pixels from the edge of the image.
Starting from the eddges of the image, set all pixels that have that colour and are connected to the edge through pixels of that colour to transparent.
The edge of the piece of clothing is now going to look a bit ugly because it consist of pixels that gain their colour from both the background and the piece of clothing. To combat this you need to do a bit more work:
Find the edge of the piece of clothing through some edge detection mechanism.
Replace the colour of the edge pixels with a blend of the colour just "inside" the edge pixel (i.e. the colour of the clothing in that region) and transparent (if your output image format supports that).
If you want to get really fancy, you increase the transparency depending on how much "like" the background colour the colour of that pixel is.
Basically, find the color of the background and subtract it, but I guess you knew this. It's a little tricky to do this all automatically, but it seems possible.
First, take a look at blob detection with OpenCV and see if this is basically done for you.
To do it yourself:
find the background: There are several options. Probably easiest is to histogram the image, and the large number of pixels with similar values are the background, and if there are two large collections, the background will be the one with a big hole in the middle. Another approach is to take a band around the perimeter as the background color, but this seems inferior as, for example, reflection from a flash could dramatically brighten more centrally located background pixels.
remove the background: a first take at this would be to threshold the image based on the background color, and then run the "open" or "close" algorithms on this, and then use this as a mask to select your clothing article. (The point of open/close is to not remove small background colored items on the clothing, like black buttons on a white blouse, or, say, bright reflections on black clothing.)
OpenCV is a good tool for this.
The trickiest part of this will probably be at the shadow around the object (e.g. a black jacket on a white background will have a continuous gray shadow at some of the edges and where to make this cut?), but if you get this far, post another question.
if you know the exact color intensity of the background and it will never change and the articles of clothing will never coincide with this color, then this is a simple application of background subtraction, that is everything that is not a particular color intensity is considered an "on" pixel, one of interest. You can then use connected component labeling (http://en.wikipedia.org/wiki/Connected_Component_Labeling) to figure out seperate groupings of objects.
for a color image, with the same background on every pictures:
convert your image to HSV or HSL
determine the Hue value of the background (+/-10): do this step once, using photoshop for example, then use the same value on all your pictures.
perform a color threshold: on the hue channel exclude the hue of the background ([0,hue[ + ]hue, 255] typically), for all other channels include the whole value range (0 to 255 typically). this will select pixels which are NOT the background.
perform a "fill holes" operation (normally found along blob analysis or labelling functions) to complete the part of the clothes which may have been of the same color than the background.
now you have an image which is a "mask" of the clothes: non-zero pixels represents the clothes, 0 pixels represents the background.
this step of the processing depends on how you want to make pixels transparent: typically, if you save your image as PNG with an alpha (transparency) channel, use a logical AND (also called "masking") operation between the alpha channel of the original image and the mask build in the previous step.
voilà, the background disappeared, save the resulting image.