I managed to show a gif almost perfectly with the disposal methods and everything, but I have a big trouble with the transparent color.
I saw other apps that draw a previous bmp on the next successfully.
I don't know how to do it.
I think I need to use transparentblt but I don't know how to set the transparent color. I work with 32-bit bitmaps, the transparent color of each frame I take correctly from the gif frame palette,
but I don't know if I should and how to set the alpha channel of the color.
In the beginning I tried to replace each transparent color with 0x80000000 and use the bitmap with both bitblt/transparentblt,
but no luck.
Maybe my problem is only the alpha channel of the transparent color? What value should it get?
I actually think my problem is only drawing bitmap on another with transparent color.
Since I have the transparent color I'll think I can do it myself
even if I'll have to transfer the bytes byte by byte.
I still don't know whether TransparentBlt API can do it though.
Related
In the last days, while I'm working on a project, I was introduced to the sprite - Byte Array.
Unfortunately, I didnt find out any kond of information about the sprite which can tell me mote about what is this and how it's works.
I really be pleased if you can give me some information and examples for sprite.
A sprite is basically an image with a transparent background color or alpha channel which can be positioned on the screen and moved (usually involving redraw the background over the old position). In the case of an animated sprite, the sprite may consist of several actual images making up the frames of the animation. The format of the image depends entirely on the hardware and/or technology being used to draw or render it. For speed, the dimensions are usually powers of two (8,16,32,64 etc) but this may not be necessary for modern hardware.
Traditionally (read: back in my day), you might have a 320x200x256 screen resolution and a 16x16x256 sprite with color 0 being transparent. Each refresh of the screen would begin with redrawing the background under the sprites, taking a copy of the background under their new position and then redrawing only the visible colors of every sprite in their new position.
With modern hardware, however, it is more efficient to pass data in a format that the driver can handle (hopefully in the graphics accelerator) rather than do everything by hand.
My WPF VS 2008 application is working with many different images that are assembled and displayed at runtime. I would like to display some white text on top of those images. My problem is that some images contain a white or light color background.
My question is - is it possible to somehow specify a property or specify a setting in the image object, BitmapImage object (where the image is loaded from), or some other WPF object such that when white pixels from one image overlap white pixels from the other image - they turn a different color so the text will be viewable?
I think it depends on how you 'draw' your text on the images. If you use e.g. a Label, you can try out the 'DropShadowEffect', see: http://msdn.microsoft.com/en-us/library/ms748273.aspx
This effect should work with all WPF objects and you can try out some transparent black soft shadows surrounding the text (a little bit like a glow).
This will only be visible in bright environments if you adjust the opacity right.
Decided to use a dark background color for the text that is only partially (.35) opaque. This means that the background color of the image comes through for the most part, but for lighter colors it yields enough contrast so that the text is viewable.
I've not fully understand the basics of Bit blit bitmaps.
I'm using the WriteableBitmapEx framework (WPF). My bitmap represents a map and what I wanna achieve is to copy a (moving) symbol into that map.
For actual copying, I use the function Blit:
_bitmap.Blit(myObject.Value.Location.ToWindowsPoint(), symbol, rect, Colors.Cyan,
WriteableBitmapExtensions.BlendMode.Additive);
where symbol is a png image(transparent background).
This works in prinicpal but I do not understand how the color (Colors.Cyan) is applied by the blend mode. I've tried out all available blend modes but I've not succeeded in getting Cyan as the color of the symbol or I got the color but then the transparent background was also copied to the source bitmap (black background).
Is 'Bliting' the wrong approach for my use case?
Thanks.
A much easier approach is to use images (corresponding WPF ui element) and layer it above the bitmap. This has also the advantage that you can move the image without redrawing the bitmap at all.
I have a problem. I need to fill (or repaint) some pixels at image, stored in Image control. This is a png image. I mean, that all black pixels should be filled with, for example, red color. How can I do this? I thought I can access directly to pixels and using XOR change special bits, but I don't know how to do this. Or maybe there is an easier way?
The GetPixel and SetPixel methods should work for what you need.
This answer has a code sample that you should be able to adopt for your use.
I'm working on a Windows Form in VB.NET 2005 and I would like to have some buttons with images (I'm talking about the plain, vanilla System.Windows.Forms.Button). I have everything set up the way I want it but the images are displaying too low on the button, such that the bottom of the icon is almost right on the bottom of the button and there is a lot of space above the image.
Here is a screenshot:
Button Screenshot http://www.freeimagehosting.net/uploads/b28a5c63b8.jpg
See how the corner of the icon is brushing up against the bottom of the button?
My button is 23 pixels high and the image is a 16 x 16 icon (converted to a bitmap so that it can be assigned to the button's Image property).
I've tried setting the button's Margin.All property to 0, and verified that the Padding.All property is 0. I've also tried changing the button's ImageAlign to TopLeft, MiddleLeft, and BottomLeft, but none of those settings seem to have any affect.
Does anyone know how I can position the image to be of equal distance from the top and bottom edges of the button? I can resize the button or the image if necessary but they are at my preferred size and I would like to keep them that way if possible.
I just encountered a similar problem, which I was able to solve by thinking really hard. (Ain't those situations great?)
The explanation
First it's important to understand that ImageAlign does NOT mean where on the button do you want the image. It means what point (pixel) on the image should be used for positioning. So if you pick "TopLeft", then the top-left-most pixel of the image will be vertically CENTERED on the button.
The problem comes in when you have a button with a centered image, whose ImageAlign is set vertically to "center", and whose dimensions are of an even number of pixels. Your image is 16x16 pixels- 16 is an even number. The middle pixel would theoretically be somewhere between pixel 8 and pixel 9. Since there is no pixel 8.5, VB rounds down to 8, thereby using pixel 8 as your positioning pixel. This the root cause of your unwanted upper margin.
Your button has an odd pixel height (23px) which means it has a true center pixel- pixel 12. VB tries to position the image's center pixel (8) on top of the button's center pixel (12). This puts 8 of the image's pixels BELOW center, and 7 pixels ABOVE center. To even things out, a 1-pixel margin appears above the image.
The solution
Pad the image with 1 extra row of pixels on the bottom. The image now has a height that's odd (17 px), giving the image a true center pixel which can line up perfectly with the button's center pixel.
That's how I solved the problem for myself. However, a simpler possible solution just occurred to me. You could probably achieve the same result by assigning the image a bottom margin of 1px. I have not tested this solution but it seems theoretically equivalent to the first solution.
Additional note: Two objects of EVEN dimensions should theoretically be able to center-align perfectly. But strangely enough, the alignment problem occurs even if the button AND the image BOTH have even dimensions. (Apparently the compiler is not consistent in the way it determines the center pixel of one control vs another.) Nonetheless, in this case, the same solution applies.
Typically, we'll set the following properties (for an image on the right, for example):
ImageAlign: MiddleRight
TextAlign: MiddleLeft
You'll want to align both the text and image in a similar fashion. Outside of that, make sure that you are setting the Image property, not the BackgroundImage property and make sure you are doing the icon to plain bitmap conversion properly. Have you tried a plain bitmap file?
Just a question: are you positive that the bitmap contains no information on the top of the note image? I have had that happen to me more than once where a crop looked right in Photoshop and came out incorrect in the live code... :)
If that were the case your code may be perfect ;)