How to draw a transparent rectangle? - java-me

How to draw a transparent rectangle in j2me?

Transparency is supported only in immutable images, i.e. images loaded from files. So you can create appropriate image. Or create transparency via filling its transparency parts with background color.

Nokia has some functions that will allow you to draw transparent rects and polygons
http://www.developer.nokia.com/Resources/Library/Java/_zip/GUID-237420DE-CCBE-4A74-A129-572E0708D428/com/nokia/mid/ui/DirectGraphics.html
However if you want it to be a generic solution you should create a transparent image in code and draw it in the appropriate position. Create a int array with size = width*height then fill it with the required color (for example 0x550000ff for semi transparent blue) and create the image using Image.createRGBImage (and setting the last parameter to true).
int[] tmpArray = new int[width*height];
for(int i=tmpArray.length;i--!=0;)
tmpArray[i] = 0x550000ff;
Image transparentRectImg = Image.createRGBImage(tmpArray,width,height,true);
Also don't forget that some old j2me devices do not support alpha transparency even in images.

Related

LibGDX - change the inside color, not border

I have a rounded square texture, drawn in paint, with black border. How can I change only the inner color without changing the border color?
EDIT: I did it, but I want to ask if it can be done without using another texture? I also wonder if there is a connection between this and 9patch as in scaling. Can we use that or is there something like that?
You can tint whatever it is what you are drawing, using SpriteBatch. This means that color you specify is multiplied with the color of the image. For example if your image is a white rounded rectangle with a black border and you tint it using the color purple then the inside will be purple and the border will remain black. You didn't provide enough information to be more specific. But if you are for example using the Sprite class then you can use the setColor method to tint it. Likewise if you are using the Image class. If you are drawing the "texture" directly using SpriteBatch then you can use the setColor method of the SpriteBatch.

MeshBasicMaterial color tints texture map three.js

I'm working with a MeshBasicMaterial to which I have applied a color.
var material = new THREE.MeshBasicMaterial({color: myColor});
at some point I need to add a texture to the material
material.map = new THREE.ImageUtils.loadTexture(...);
this works fine but the color of the material is tinting the texture.
I realise I can change the color of the material to white to remove this tinting but cannot find a a way of deleting the material's color or changing the way the color and texture blend - is this possible ? I'm trying to avoid creating a new material and replacing if possible.
demonstrated in Lee Stemkoski's examples - change map to 'grass' and then change the material color
http://threejs.org/docs/scenes/material-browser.html#MeshBasicMaterial
By the fact you can set the material's .map after the fact, you should be able to set the material's .color after the fact.
material.color = myColor;
Of course, this new color should be white for your texture to be visible and not black.

color blending with GDI+

I am refering to a older question saying color blending with GDI+
Using GDI+ with Windows Forms, I want to be able to draw with a pen and blend color based on the destination pixel color.
For example, if I draw a line and it passes over black pixels, I want it to be a lighter color (like white for example) so that it's visible. When that same line passes over white pixels, it should be a darker color (black for example) so that it's still clearly visible.
the answers says to use a color matrix for transformation
so i started implementing it..
My image is present in raw data format in rgb48
Gdiplus::Bitmap image(input.width,input.height,input.width*6,PixelFormat48bppRGB,(unsigned char*)rgb48);
Gdiplus::Image *images= image.GetThumbnailImage(input.width,input.height);
Gdiplus::TextureBrush brush(images);
Gdiplus::Pen pen(&brush);
Gdiplus::ColorMatrix matrix={
-1.0f,0.0f,0.0f,0.0f,0.0f,
0.0f,-1.0f,0.0f,0.0f,0.0f,
0.0f,0.0f,-1.0f,0.0f,0.0f,
0.0f,0.0f,0.0f,1.0f,0.0f,
1.0f,1.0f,1.0f,0.0f,1.0f,
};
Gdiplus::Graphics gfx(&image1);
Gdiplus::ImageAttributes imageAttr;
imageAttr.SetColorMatrix(&matrix);
gfx.DrawImage(images,Gdiplus::Rect(0,0,input.width,input.height),0,0,1024,1024,Gdiplus::UnitPixel,&imageAttr);
I am not getting what i expect..Can some one help me in finding the mistake i m doing.
You can use the alpha component of a color to specify transparency, so that colors can be combined. However, if you want the combination to be something other than the alpha blend, you must draw the pixels yourself. You could first draw into a transparent bitmap, then render that onto the destination pixel by pixel.

How to overlay color on texture in libgdx?

I'm using texture and textureAtlas in libgdx.
This textures loads images of white circle.
How can I overlay its color with another color?
Or maybe their is another approach for this?
private final static TextureAtlas textureAtlas = new TextureAtlas(Gdx.files.internal("spritesheet.atlas"));
private final static TextureAtlas.AtlasRegion texture = textureAtlas.findRegion("Bubble.001");
EDIT:
As I said I have a white circle and I want to make it red (without the need for another image with a red circle)
You can use the lerp method in Color class.
actor.setColor(Color.WHITE.cpy().lerp(tintingColor, .5f));
lerp changes your Color object, so use the cpy command before it to preserve the original color. In this case I use WHITE as my original color, which preserves the color of your Actor's texture. lerp will overlay the tintingColor with a strength of 50% in this case.

Can an SVG object have both a fill colour and a fill pattern?

I'm working with SVG using the Raphael library. I can apply a fill colour to an object like so:
circle.attr({fill: "#ff0000"});
And this also works (though the Raphael documentation doesn't mention it):
circle.attr({fill: "url(pattern.png)"});
I am able to use transparent PNGs as fill patterns, and transparency works as expected. The svg object is completely transparent where the fill pattern image is transparent. But what I would like to do is specify both a fill pattern image and a fill colour, so that the colour would show through where the pattern image is transparent - similar to the 'background' property using CSS, for example. Is this possible with SVG?
You can define a pattern that has a rect with a fill, and an image that is your png on top of that rect. Then use the pattern as fill for the circle (or whatever element you want).
This means stepping outside of Raphaël, or extending it to do what you want. Note that what ({fill: "url(pattern.png)"}) does is to create a pattern element and and append an image element pointing to the given url. It's quite possible to hack Raphaël to allow you to pass a color too, and then you deal with that in the code that creates the pattern by creating a rect of the same dimensions as the image with the given fill color.
I should say that if you want it to work with IE<9 then you probably need to implement it in VML too.
Other options include drawing two shapes, one with color fill and the other with the raster image fill. Yet another is to make the png include the background color so that it's not transparent.

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