I have issue while working with corona screen positioning that the start Y=0 of the content does not belong to top point on the screen, it resides rather a bit lower than expected,
I have listed different sample of current
Y values on the attached image. Here is my config code:
application =
{
content =
{
width = 768,
height = 1024,
scale = "letterBox",
fps = 60,
},
}
The letterbox mode means you may have black bars on top and bottom or left and right side of the screen. That is why (0, 0) is not always positioned in top-left corner of the screen. Use (display.screenOriginX,display.screenOriginY)
as top-left point of the screen instead of (0, 0) to solve problem.
Read more about Content Scaling.
Related
I am building a Warehouse map in 2D with fabricjs where I am displaying their racking systems as a series of rectangles.
As a first "layer/group", i add all bays as groups containing a rectangle and text, both positioned at the same (x,y). They also have both an angle set to fit their orientation in the space.
As a second "layer/group", i add groups containing a circle and text, representing the bay's number of issues. The (x,y) also fits the bays. This way, all my issues are always on top of the bays and the center of the group fits the rotated corner of the bay.
On the first paint, all is well aligned. Once they're shown on the page, the user can create new issues, so I am trying to position the issue group fitting the original (x,y), but since it can all be panned and zoomed, I am having a hard time positioning it where it should be.
I've been looking at their explanations about transforms, but I can't figure who the boss should be and thinking that having nested groups may also be why I am all mixed up.
By doing:
const gMatrix = matchingBay.group.calcTransformMatrix(false);
const targetToCanvas = fabric.util.transformPoint(matchingBay.aCoords.tl, gMatrix);
I am on the bay, but on the "group" corner, which is not what I am looking for. (x,y) will be one of the corners of the rectangle in the group, that may have been rotated.
By specifying the original (x,y) in this code will get me way off the actual painting zone.
So, my question is, how do I get the transformed (x,y) so I can add my issue group at those coordinates?
[EDIT]
As the suggestion of spring, it made me realize I can use the rotated rectangle's transforms to find its coordinates, so I tried:
const rect = matchingBay.getObjects()[BAY_RECTANGLE_INX];
const gMatrix = rect.calcTransformMatrix();
const targetToCanvas = fabric.util.transformPoint(rect.aCoords.bl, gMatrix);
Bottom left corner is where I wish to add the new Circle. After rotation, the bottom left is now the bottom right. But I am still off. As shown, the red circle should be on the corner. It looks like the rotation has not been applied.
qrDecompose gives me something that seems right:
{angle: -90, scaleX: 1, scaleY: -1, skewX: 0, skewY: 0, translateX: 6099.626027314769, translateY: 4785.016008065199 }
I realized that I was not thinking it the right way. Since I have the rectangle already in hands, I just had to get its own transformation and resolve the corner by my own, the following fixed my issue:
{
[...]
const rect = matchingBay.getObjects()[BAY_RECTANGLE_INX];
const gMatrix = rect.calcTransformMatrix();
const decomposed = fabric.util.qrDecompose(gMatrix);
const trans = fabric.util.transformPoint(new fabric.Point((decomposed.scaleX * -rect.width) / 2, (decomposed.scaleY * rect.height) / 2), gMatrix);
const top = trans.y;
const left = trans.x;
[...]
}
Since the matrix is bringing the center point of the rectangle, I can get the corner by substracting its width and height and then transforming the coordinates to find out where the matrix puts it.
I have a Text in fabricJs. I set top and left.
This sets the aCoords properly to those values.
However the oCoords dont match. And the Text is not displayed at the right position.
I suspect that I need to set to oCoords somehow. So that the Text is displayed at the right pixel coordinates (top & left) on the canvas.
aCoords and oCoords are two different things and should not be in sync.
In your comment you speak about scaled canvas.
Top and Left are 2 absolute values that represent the position of the object on the canvas. This position match with the canvas pixels when the canvas has a identity transform matrix.
If you apply a zoom, this coordinates diverge.
To get the position of pixel 300,100 of the scaled canvas on the unscaled canvas, you need to apply some basic math.
1) get the transform applied to the canvas
canvas.viewportTransform
2) invert it
var iM = fabric.util.invertTransform(canvas.viewportTransform)
3) multiply the wanted point by this matrix
var point = new fabric.Point(myX, myY);
var transformedPoint = fabric.util.transformPoint(point, iM)
4) set the object at that point.
I'm using a CIPerspectiveTransformWithExtent filter to apply homographies (perspective warp) to images on OS X. So far, so good, and I can get the desired warping applied to my images.
I'm still struggling however with the border behavior. I would like the output of the filter to be clipped outside the original image domain:
I managed to do it for the lower and left borders by shifting the origin of the inputExtent rectangle of the correct amount. For example, if the lower left corner is projected to x = -10 then using extent.origin.x = 10 will correctly clip the left border;
on the other hand, the upper and right borders are always shown in the output image. For example, if the rightmost corner is projected to x = width + 10, setting the extent via extent.origin.x = 0, extent.size.width = width; does not work an the rightmost corner remains visible.
Am I doing anything wrong here? or maybe I'm not trying the right way to achieve my goal?
I'm trying to separate the background of the graph grid in 3 areas using this code:
int[] data = {0xff000000, 0x80008000, 0xff000000};
bgBitmap = Bitmap.createBitmap(data, 1, 3, Bitmap.Config.ARGB_8888);
RectF rect = plot.getGraphWidget().getGridRect();
BitmapShader myShader = new BitmapShader(
Bitmap.createScaledBitmap(bgBitmap, 1, (int) rect.height(), false),
Shader.TileMode.REPEAT,
Shader.TileMode.REPEAT);
plot.getGraphWidget().getGridBackgroundPaint().setShader(myShader);
So scaling a 3 pixel bitmap to the graph height and repeating it over the whole domain area.
However the resulting graph show that the background seems to be shifted up a bit.
It looks like the shift size is about equal to the domain label height.
How can I fix this?
Hm cannot post picture because of 'reputation' sigh.
Link to the example graph: http://marcel.mesa.nl/androidplot.png
I think you're running into the issue mentioned near the end of this thread. Essentially, the origin of the shader is the top-left corner of the screen, not the top-left corner of component for which the background is being drawn using the shader. The solution is to translate to the top-left point of the graphWidget like this:
RectF rect = plot.getGraphWidget().getGridRect();
Matrix m = new Matrix();
m.setTranslate(rect.left, rect.top);
shader.setLocalMatrix(m); // where shader is your shader instance
I have 3 sprites. Left edge, right edge, and repeating center which has 1 pixel width but is scaled up. The problem is that the scaled sprite fades out the farther away it is from the center:
I've tried using CCTexture's setAliasTexParameters but the result doesn't look good:
How do I get the antialiased looks in the first picture but without the fade out problem?
You could try this on the sprite:
// These parameters set the texture properties:
// minifying filter - linear interpolation,
// magnification filter - linear interpolation,
// texture repeat in S direction,
// texture repeat in T direction (*)
ccTexParams params = {GL_LINEAR, GL_LINEAR, GL_REPEAT, GL_REPEAT};
[sprite.texture setTexParams:¶ms];
// This explicitly sets the contentSize of the sprite to (10, 200),
// but also sets the "window to the texture" to this rectangle:
[sprite setTextureRect:CGRectMake(0, 0, 10, 200)];
You have to tweak these settings, but hope you get it.
You don't have to scale the sprite.
(*) For S and T check this: Difference between U V and S T texture coordinates