The problem with rendered images is that the left side triangle isn't smooth enough. There is a bit of jagged edge on the slopes. This was found in the draw9patch tool's preview too, but couldn't tackle it so far.
Any hint regarding solution will appreciated.
This happens because you specify too wide area for the height shrink/stretch. Put just one black pixel in the leftmost pixel column (it's tricky where to put it, actually. I'd put one pixel in the very top of your image and one more - in the very bottom).
Related
Can anybody advise me on how to setup a splash screen to work cross resolution?
I have tried re-sizing a png file to different dimensions and placing the image in the ldpi,mdpi,hdpi folders, but the image still looks stretched/squashed depending on the device.
Is there a way to place a logo centre of the screen with a white background, i'm happy to use one size of logo even as long as it sits in the middle and looks ok¬?
Does anyone have any advice?
Cheers
Paul
Have you heard of/considered using a 9 patch version of the logo? A nine patch image allows you to define areas of an image which can be stretched. If you create your logo png file with a white background and then set the white area as stretchable it will then fill your container nicely but the logo part of the image will not distort at all.
In your android-sdk directory, under the tools subdirectory, execute a tool called draw9patch
./draw9patch
Drag your image in there. Use the left view for drawing pixels on the top and left sides. Use the right view for inspecting how your image will stretch on different devices.
OK, the answer has EVERYTHING to do with the stretchy areas of your 9patch image. I found the answer by pinging the github question. A user sent me to another discussion where someone had cracked it.
The main issue is that most 9patch tutorials explain how to stretch buttons, but none detail how to center an image.
Look for the green/blue/red image a little more than half way through the discussion.
http://community.phonegap.com/nitobi/topics/stretched_9_patch_splash_screens_android
The key for me was to look at the edges. It's really hard to see (for me at least), but you can barely make out the black marks along the edge that define the stretchy areas. top has 2 small areas (on the green), left has 2 small (on the green), bottom has one long (on the blue), right has one long (on the blue).
Consequently, I find this one image (as hard as it is to see the lines) a better instruction on how 9patch works than all of the tutorials I've watched.
I uploaded a screenshot what I'm doing: http://www.fotos-hochladen.net/uploads/bildschirmfoto0knmxp974g.png
I want the yellow area to be always the same size, whereas the transparent area at the top should scale. The problem is, that the whole image gets transparent with that configuration.
If I add another dot at the left side it works, but then the yellow area also scales...
If I understand the docs correctly, this should work as I thought.
Thanks in advance.
Try un-marking the farthest right pixel along the top edge. I'm not exactly sure why this works, though.
NinePatch:
Screenshot:
Layout XML:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:background="#ffffff">
<LinearLayout
android:id="#+id/edit_tray"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true">
<View
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#drawable/trash"/>
</LinearLayout>
</RelativeLayout>
Desired Results:
The "edit_tray" represents a UI element that will be toggleable. When edit mode is off, the "edit_tray" (and therefore the trash can icon) are "gone". When edit mode is on the "edit_tray" is visible and overlaid over the ScrollView contents.
There are two elements to the trash can icon: The icon itself and the linear gradient behind it. The NinePatch image contains three stretchable areas and one static area to accommodate these elements. The trash can icon in the middle of the graphic is static and should appear directly in the horizontal center and on the bottom of the screen. The gradient should stretch across the bottom of the screen from one side to the other.
The Bug?
The NinePatch image contains only one pixel of stretchable area on either side of the image horizontally. The effect of which should be that the trash can icon appears directly in the center (1 pixel on left side == 1 pixel on right side). However, as you can see in the screenshot above that is not the case. Note: this screenshot was taken from my test phone, a T-Mobile G2. The same effect can be seen in the emulator. However, in the draw9patch preview and the eclipse Graphical Layout view the image is perfectly distributed.
I've tried several different methods to try to find out where the bug is and to try to fix it or work around it. Including: using ImageViews instead of Views (same effect), using android:scaleType="fitXY" (same issue), checking at runtime that the width of the screen and the width of the "edit_tray" are the same (they are), using two different images for gradient (as edit_tray background) and icon (as ImageView src) (create another problem where the two images were not overlayed on each other. Fixed by setting an absolute height on both), etc.
The Answer, the Workaround, and the Real Question
I did some testing using some simple NinePatch images with up to six stretchable areas per side. I noticed there were some issues displaying them in at least one of the testing cases (phone, emulator, draw9patch, Graphical Layout in eclipse).
I decided to try to expand the image horizontally so that there was more of the linear gradient showing on the edges of the trash can icon. I made the image 128x64 (previously 64x64). I made more of the edges part of the stretchable part to try to curb any bad math (?) that was happening to the image. Draw9patch reported bad sections so I put it back to just the two pixels, one on either side. It worked! The icon is directly in the center of the screen now! I don't know why, but without changing the actual stretchable portion of the image, only changing the width of the image to 128, it works now.
I tried resizing the image back down to around 100px wide to remove some of the redundant pixels and the error came back! Not only did it come back, but the icon was placed at exactly the same spot offset from the center of the screen. I can't figure out why this would happen this way.
Anyone have any ideas? Is this a bug?
I currently have this working given the workarounds I described above, but if anyone has any suggestions I'm listening.
Make your 9 Patch image with using 4 points as I have done in this..and it will work.
Tips for Creating 9 Patch Image.(not a designer,telling you my funda)
Put points on Left and Top
If you have some text or image in between ..then put point on left
and right of image and top and bottom of that image or text.
Always see the no of space left and no of points on both sides(left-right and top-bottom) are equal.
Always check once the preview or right side before using check in 2x
to 6x
From my experience with the draw 9-patch tool there is an automatic 1px offset on each side of the image. Given this information if you were using just this one pixel offset your image was actually not being stretch the way you would imagine.
This can be seen by the fact that when you used a 2px offset it worked perfect.
Also the 9-patch images have a tendency of showing up in eclipse exactly how you would think... but then appearing different on the phone/emulator.
Learning the 9-patch tool is def a great thing as it allows greater customization. Another tip, if you want to do something like replace any android 9-patch with your own alterations - then just copy the 9patch that exists in the SDK and alter it. For some reason 9patch images in the SDK have weird offsets. Doing this will guarantee you don't get weird responses from your 9-patches. An example of this - I outline an editText in red when bad input is given.
The SDK images can be found in SDK->platforms->[plateform-you-want]->data->res-drawable-[you-choice]
You can also look at the SDK 9-patch images to help understand how the 9-patch-tool works.
Hope this give a little more insight.
Here are some good links:
http://developer.android.com/guide/developing/tools/draw9patch.html
http://android10.org/index.php/articlesother/279-draw-9-patch-tutorial
http://jaanus.com/post/7878186745/how-does-androids-nine-patch-tool-work-from-a
Maybe it's bug in nine-patch drawing, or just error resulting from rounding.
However, I don't like your approach of drawing this icon. You try to position your screen element using something that is not designed for this task.
You should draw it other way: create some container view (FrameLayout) with gradiend background. Then on top of that position ImageView with trash can. Neither of these 2 images need to be nine-patch, gradiend would fill entire view, trash can would be drawn without scaling.
Although there's overdraw in area of trash view, CPU time is not wasted in nine-patch areas computations.
You would use layout system for exact positioning of your trash icon. Certainly you would get expected result, since UI layouts are well tuned, and made for purpose of positioning screen elements. Nine-patch images are used for other purpose (where pixels shifted here or there a bit should not matter).
As #jjNford said - it's bad practice to work with images in this way.
For this task the best solution is to create "trash" icon with transparent background, and create shape drawable with gradient. So, you can remove unnecessary LinearLayout and use only ImageView:
<ImageView
android:id="#+id/edit_tray"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:src="#drawable/trash"
android:background="#drawable/gradient_background"/>
Docs for shape drawable.
EDIT
Just check your image - it starches fine on SE Xperia 2.3.3
I got a transparant 9patch image which has the 9patch lines showing trough.
This is the output:
Obviously I don't want the horizontal lines to be visible.
This is how I created the 9patch:
This is the final image that is used in the application:
AFAIK the 9patch is correct. What do I need to change in order for the horizontal lines to disappear?
The unwanted lines come from the fixed (non-stretched) parts of the ninepatch overlapping. This is happening because you are drawing it at a pixel height that is smaller than the sum of the heights of the fixed sections.
As #kcoppock said above and then curiously retracted, the left hand edge should be solid black where it is vertically stretchable.
Try connecting the two dots on the left edge, making it a solid line, see if that fixes the problem. You also only need 1 dot along the top for the exact same result.
EDIT: Ignore the above, I don't know what I was thinking. Connecting the line on the left is definitely not allowed, that's my mistake.
EDIT: Ignore the above edit -- Reuben's right. :)
I don't know that it's what's causing the problem, but I noticed that along the top edge, there are some pixels that are not fully transparent (e.g. pixels(5,0) through (28,0) are a very light shade of gray) likely due to some bleeding over of the anti-aliasing of the shape. Try flattening the image, and erasing all the outermost pixels, other than the black pixels, of course. That should only cause a compiler error, though, it shouldn't cause that sort of an artifact. I wish I could test it myself right now but I can't.
I'm trying to create some 9patch images that have some text as their content. I define the stretchable area with a black pixel line top and left. And I define the content area with a black pixel line right and bottom.
However, it seems as though Droid is adding padding to the top and bottom of the content area, messing my layouts up. Has anyone else experienced this?
You say you're putting a black pixel line for the top and left? For the top, you should place just a single pixel for the stretch point. For the left, you can place either one or two pixels (two if there are two separate places you would like to stretch). Let me know if I am misunderstanding you though.