I'm very new to AEM and I'm trying to reduce the image size by using named transform image servlet in AEM 6.3. After reducing the image size using resize property, the image quality goes down terribly.
I've also tried using attributes sharpen and quality however I'm not able to understand their proper usage even after going through the adobe docs.
This is the original image resolution
1600 x 530
This is the image configuration that I've tried so far:
bounded-resize:width=1423&height=471&upscale=true (using this only reduces the image quality a lot)
quality:quality=82 (this changed nothing)
sharpen:op_usm=3.5,20(this distorted the image completely, sort of oil paint effect)
Above configuration maintains the aspect ration but not the quality.
Need to know what wrong I've done in this and how do I REDUCE THE IMAGE SIZE WHILE MAINTAINING THE ASPECT RATIO AND IMAGE QUALITY.
You should check the order of Image Transformers in your transformer configuration. The documentation states:
Order matters when defining your image transformation rules. For example, a resize then crop can yield significantly different results than a crop then resize.
I am not a 100% sure which makes more sense: Resize and Crop or Crop and Resize. But that would be easy to validate:
Create two transformer configurations. Both should just contain the resize and crop setting but in a different order. Call both of them (with the right URL) and then compare the resulting images.
how do I REDUCE THE IMAGE SIZE WHILE MAINTAINING THE ASPECT RATIO AND
IMAGE QUALITY.
As a best practice, to achieve a high image quality and small file size, start with the following combination of parameters:
fmt=jpg&qlt=85,0&resMode=sharp2&op_usm=1.75,0.3,2,0
This combination of settings products excellent results under most circumstances.
For further reading and learning, Refer to this
Related
I'm trying to implement a simple LUT color grade in a metal shader. It works with a color LUT, but when the LUT is grayscale, problems crop up. First, loading the grayscale image causes an "image decoding failed" error, which is fixed with this bug workaround.
By recharacterizing the image as a texture in the asset bundle, it loads successfully, but there's banding on the output image. Sure enough, capturing a GPU frame shows that banding has been introduced in the texture:
This banding doesn't appear when doing a Quick Look in the asset bundle, or on the source PNG. Inspecting the texture's pixel format shows that it's been encoded as ASTC_4x4_sRGB, which Apple documentation states is a compressed format for low-dynamic range content. It seems as though this compression may be responsible for degrading the LUT texture. Normally when working with LUTs, I take care to avoid any compression, but I can't find a way to disable compression or force a pixel format in MTKTextureLoader.
I've also tried various MTKTextureLoader options, including enabling/disabling sRGB, mipmaps, etc.
Any ideas on how to fix the banding?
It's important to understand that when using MTKTextureLoader with texture assets in an asset catalog, most runtime texture loader options are ignored. This may not be documented, but it is currently the case.
You may be able to avoid this automatic compression (which is well-intentioned but both clumsy and too aggressive) by selecting your asset in the Xcode asset catalog editor and setting its Pixel Format explicitly to something like "8 Bit Normalized - RGBA", which maps to .rgba8Unorm at runtime.
What are the limits on GMSGroundOverlay? This would be things like file size, resolution, etc..
I'm using Google Maps SDK 1.5. I created a ground overlay from an image that was 4836x5557 72 dpi 6.6 MB. That image did not show up. When I reduced the image to 3481x4000 72 dpi 4.5 MB, that overlay image did show up.
I did try some permutations of resolutions and file sizes but couldn't nail down the pattern. I did not see any documentation of limits in the docs nor headers.
This is important to me as we have customers who use want map overlays, and to be able to provide them up front with the constraints for the overlay graphics is useful and saves much time for all involved.
Thank you.
Overlay is rendered using OpenGL as a single texture, so the limitation on its size is probably the same as limitation on OpenGL texture size.
On the latest devices maximum texture size is 4096×4096:
https://apptyrant.com/2014/04/19/max-opengl-texture-sizes-for-various-ios-devices/
The solution is either to limit the overlay size or to use Tiles API.
I am trying to create a background image on a webpage, which is similar to the 404 page used on tumbler...
http://testing404image.tumblr.com/
Here we can see a PNG which is 1623*1064 pixels, yet appears reasonably smooth gradient wise.
The direct link for the image is
http://testing404image.tumblr.com/images/status_bg.png?2
When I try to create a similar PNG (different colors, but same size) in Photoshop CS4 for Mac, the resulting file ends up at > 400k, whereas tumblers is 90k
Ive tried playing with all Photoshop options, including reducing number of colors to 55, but I cannot get the image below ~240k.
Ive also tried various optimising tools such as ImageOptim (http://imageoptim.com/) but to no avail.
Are there any properties of this PNG which result in a such a low file size?
I tried using JPG, thinking its better suited to gradient images, but even a 100% quality JPG resulted in noticeable aliasing, which an identical content/size PNG didnt have.
Thanks for any advice
Hi there changed the colours with
Image > Adjustments > Hue/Saturation - In Photoshop CS4
and this is the result:
as you can see it's almost the same size (75k).
Try playing around under the
Image > Adjustments
to get the color you are looking for and save as png with NONE for interlace.
Photoshop is not very good with PNG: I simply opened and saved it with the humble xnView (maximum compression), and got 74K. You can also convert it to paletted-image, and do some extra little tuning - PNGoptim gives me a final size of 64.548. I would't expect anything much better than that, the image is just too big.
BTW, be aware that using a gradient that is so big and so smooth that it a digital image (with 8 bits per pixel) cannot represent it without some banding. That image is really oversampled (you could resample it at 25% or less and display it scaled, and the result would be basically the same)
The actual reason is the source image your looking to have a lower gradient quality than the one you are making.
Just uncheck the Dither option (from the top toolbar in Photoshop) when filling the gradient color. the quality and smoothness of the gradient is decreased and therefore you get a very smaller file sized PNG output.
i am converting the image into thumbnail format and sending it to server and i want to convert it back to original size while receiving can any one please tell me how to resize the image to original without loosing quality.....
i tried directly to displaying the image in image view but the quality of the image is missing ...
can any one please help me how to maintain the quality of the image .......
Downscaling is irreversible, some information lost forever.
What you're asking isn't possible. You can't enlarge an image while maintaining the same quality. If you think about an image as a mapped array of pixels (literally, a "bit-map"), this makes sense. The image is saved with a fixed amount of data, and that's all you have to work with when you resize it. Any examples to the contrary (like TV shows) are purely fictional.
Investigate using vector graphics instead, which can be resized at will without a loss of quality.
you simply can not convert an image from thumbnail to original size and retain the quality it had in its original size.
if you want to display the image full-size, you have to send the full-size image.
You could think about using a Vector image? They do not lose quality when resized. But I have no clue whether you can use them for thumbnails in iOS.
See this wiki page for more info about Vector graphics.
I'm writing a card game for the iPhone, and I'm not sure about the best strategy for displaying the cards. I have a basic prototype that creates a UIImageView that can be dragged for each card with a dummy image. I wanted to use one large UIImage that contains the faces of all of the cards, and then have each draggable UIImageView display a part of that image. I must be misunderstanding what setBounds is for - I thought that controlled which part of the underlying image is displayed. So, two questions:
Is this the right approach?
How do I display just a part of the image?
Depending on your resolution, this might not be the best approach.
From Apple:
You should avoid creating UIImage
objects that are greater than 1024 x
1024 in size. Besides the large amount
of memory such an image would consume,
you may run into problems when using
the image as a texture in OpenGL ES or
when drawing the image to a view or
layer. This size restriction does not
apply if you are performing code-based
manipulations, such as resizing an
image larger than 1024 x 1024 pixels
by drawing it to a bitmap-backed
graphics context. In fact, you may
need to resize an image in this manner
(or break it into several smaller
images) in order to draw it to one of
your views.
Now, you are talking about breaking it up into several smaller pieces, but given UIIMage's caching, I am not sure what happens to memory every time you access the image and copy a sub-rect out of it. I think the approach I would take is to have an array of images, instead of one big one.