I'm developing a react native app that allows the user to take a photo (or choose one from the gallery) and automatically attaches it to an email. I'm using react-native-image-picker to select the image, which allows me to optimize the image in terms of
quality = 0 - 1
max-height = 1024
max-width = 1024
The resulting image is exactly what I want, either 1024x768 (landscape) or 768x1024 (portrait) and usually comes in under 100kb.
However, before sending the mail, the user is still presented with an image resize prompt. Since the image is already optimized, I would like to suppress (skip) this prompt. Is there anyway to bypass this prompt?
Furthermore, the prompt is inaccurate. The below image shows the prompt for an image that was pre-optimized to a size of 94kb. To email this full size, fully optimized image, the user must choose "Actual Size". Any other option resizes the image's dimensions and reduces the file size. As you can see, it inaccurately reports that "Actual Size" would be 674kb rather than the actual 94kb. So, if there's no way to suppress the prompt entirely, is it possible to make the size estimates more accurate?
UPDATE: An Insight
I noticed this option is not presented when attaching PNGs.
Related
I noticed that my app sends icons to the Windows tray with a size of 16x16 pixels--and my Vista PC I've got a doublewide taskbar that appears to show icons at 18x18. The resizing artifacts on my app's icon look awful. How can I ask Windows what size the icons should be?
Edit
I'm generating the icon dynamically, with a pixel font text overlay. It seems wasteful to generate a bunch of icon sizes dynamically, so it would be nice to avoid building an icon with all the "possible" sizes (not that I'm even sure what those are).
GetSystemMetrics(SM_CXSMICON) returns 16--the incorrect value.
GetThemeBackgroundContentRect didn't help, either.
Create your icons in multiple formats, and let Windows select the one it wants.
Here's the Wikipedia article on the .ico format.
If you really need to know, GetSystemMetrics with a parameter of SM_CXICON or SM_CYICON will tell you the width and height that Windows wants to load.
Mark's core answer is the right one: Create your icons in multiple formats and let Windows choose the right one. Don't forget to do 32x32 and 64x64 icons for HighDPI scenarios.
But SM_CXICON/SM_CYICON won't necessarily return the size that will be used in the taskbar. The taskbar chooses the right icon size for it's size (this is much more important in Window 7).
Just provide appropriately sized icons and you should be ok.
Your best bet may be GetThemeBackgroundContentRect passing TBN_BACKGROUND as iPartId for the tray notify background.
GetThemeBackgroundContentRect should return the size defined by the current theme that may be used for drawing without overlapping the borders of the parent element. If I'm reading this correctly, that would be the largest sized notification icon permissible and presumably the size that is being used.
Testing with multiple DPI settings is probably the easiest way to tell if this is returning the correct value.
Per the NOTIFYICONDATA documentation:
If only a 16x16 pixel icon is provided, it is scaled to a larger size in a system set to a high dpi value. This can lead to an unattractive result. It is recommended that you provide both a 16x16 pixel icon and a 32x32 icon in your resource file. Use LoadIconMetric to ensure that the correct icon is loaded and scaled appropriately. See Remarks for a code example.
...
...
// Load the icon for high DPI.
LoadIconMetric(hInst, MAKEINTRESOURCE(IDI_SMALL), LIM_SMALL, &(nid.hIcon));
...
So, creating icons dynamically really isn't the best option. You should provide multiple icons of different sizes statically in your program resources and let Windows choose the best one it wants.
I'm having a real hard time understanding this, but let's say I have an iOS app for both iPad and iPhone and I want to download an image from a server and display it in full screen.
I have read that the iPad pro has a resolution of 2732x2048 and if we want to display an image in fullscreen we would need to download the image with this size right? However, I also read that the image should never be over 300KB. I was not able to bring an image with this size under 2MB (I used JPEGmini for example to reduce size).
And I don't think that iPhone user would need to download such a huge image, so my question is: what resolution should my images be on the server and how can I manage to keep them in a rational file size. Also should I upload multiple images for different devices? If so, how many and at what resolutions?
Isn't the problem merely that you are holding incompatible beliefs? This is the belief that is giving you trouble:
I also read that the image should never be over 300KB.
Let go of it.
Clearly it is right to say that the image should be no larger than needed for display. But an image to be shown as a 3x scale image on the iPad pro needs to be 2732x2048. So that's that.
(You could, alternatively, use an image 2/3 of that size and show it as a 2x scale image. It wouldn't look quite as good as the 3x scale image, but it might be acceptable.)
On a smaller device, yes, you should scale down the image in code, so that you are not holding in memory an image larger than needed for display. But in this case, you need the large image for display.
I am displaying a grid of images (3rows x 3 columns) in collection view. Each image is a square and its width is determined to be 1/3 of collectionView's width. Collection view is pinned to left and right margin of the mainView.
I do not know what the image height and width will be at runtime, because of different screen sizes of various iPhones. For example each image will be 100x100 display pixels on 5S, but 130x130 on 6+. I was advised to supply images that exactly matches the size on screen. Bigger images often tend to become pixelate and too sharp when downsized. How does one tackle such problem?
The usual solution is to supply three versions, for single-, double-, and triple-resolution screens, and downsize in real time by redrawing with drawInRect into a graphics context when the image is first needed.
I do not know what the image height and width will be at runtime, because of different screen sizes of various iPhones. For example each image will be 100x100 display pixels on 5S, but 130x130 on 6+
Okay, so your first sentence is a lie. The second sentence proves that you do know what the size is to be on the different screen sizes. Clearly, if I tell you the name of a device, you can tell me what you think the image size should be. So, if you don't want to downscale a larger image at runtime because you don't like the resulting quality, simply supply actual images at the correct size and resolution for every device, and use the correct image on the actual device type you find yourself running on.
If your images are photos or raster type images created using a raster drawing tool, then somewhere you will have to scale the original to the sizes you want. You can either do this while running in iOS, or create sets up front using a tool which can give you better scaling results. Unfortunately, the only perfect image will be the original with everything else being a distortion of the truth.
For icons, the only accurate rendering solution is to use vector graphics. Tools like Adobe Illustrator will let you create images which you can scale to different sizes without losing clarity. Unfortunately this still leaves you generating images up front. You can script this generation using most tools and given you said your images were all square, then the total number needed is not huge. At most you need 3 for iPhone (4/5 are same width, 6 and 6+) and 2 for iPad (#1 for mini/ipad1 and #2 for retina).
Although iOS has no direct support I know of for vector image rendering, there are some 3rd party tools. http://www.paintcodeapp.com/ is an example which seems to let you import vector images or draw vector images and then generate image code to run in your app. This kind of tool would give you what you want as the images are now vector drawings drawn at the scale you choose at run time. $99 though.
There is also the SVGKit (https://github.com/SVGKit/SVGKit), but not sure how good/bad this is. It seems to let you simply load and render direct from SVG files. Might be worth trying.
So in summary, I think you either generate the relatively small subset up front using a tool you can control the output from, take the hit in iOS and let it scale the images or use a 3rd party vector to image rendering kit which would give you what you want.
I am using JQM with HTML5 boiler plate. My objective (for tests purposes) is to have in a desktop browser, an overall div that will show me the expected size areas of my app on a real device. In a desktop browser, however, the width compared to the iphone4 browser width layout do not seems to match. I do not wish to change the viewport meta definition, although I suspect that it is my problem. Can somebody explain to me:
Why the size of a div of size 640 x 960 px (with a border of 1 px and a position of absolute) does not reflect the same size area appearance on the actual device with this type of setup ?
Regards.
Just use Chrome's Developer Tools. You can choose to spoof your User Agent as well as the device metrics for different devices.
When in Chrome:
Press F12.
Click on the gear icon to the bottom right (settings).
Click on the Overrides tab.
Here you can choose to change your User Agent string or override the viewport of your browser to match specific devices (like the iPhone). If you change the User Agent string to mimic an iPhone then the Device Metrics should auto adjust to be the proper size for the same device.
Note that you must keep the Chrome Developer Tools open, as soon as you close them you lose the UA spoofing and Device Metrics spoofing as well.
To directly answer your question, different screens have different pixel densities, so a screen with higher pixel density will show the same number of pixels in a smaller physical area.
As an add-on,
When dealing with CSS Media queries there is a difference between the
device-width and the
width.
For the iphone4, for instance, although the resolution
(width x height) is equal to (640 x 960),
the device is actually presenting
(device-width x device-height) as equal to (320 x 480)
From here we observe that each CSS pixel is handled by 2 screen resolution pixel. This is the consequence of the 2 different size.
This help: Pixel density for different devices
The BB OS 5.0 supports images for context menus. The API documentation says the image will be scaled to fit a square set by the height of the menu font. I find that totally unhelpful.
The only way I can explain that method of calculation is due to screen resolution and DPI. But since the 5.0 OS is only valid on a handful of devices with similar screen sizes, I reckon they can specify the actual icon size they use.
I'd like to choose an icon size that's closest to the default menu font height so that the they look OK.
What size do you use? Do you even use this feature?
I haven't used it yet, but I would recommend using any square ratio maybe up to 64x64; the problem is that with new devices on the horizon (eg rumored tablet - with much bigger display) it won't necessarily be practical to target a specific screen size.