I'd like to create a class for an electronic project based on a matrix of leds, like the Adafruit Led Backpack . The project is a graphical editor for all the leds for a backpack of any size. Therefore, I've thought of QMatrix 4x4 since under this size no physical matrix exists. After some searches Qmatrix4x4 seems strongly related to a 4x4 matrix -ie : overloading seems requiring a lot of work- and QGenericMatrix has to few functions . Besides, using an external lib like Eigen is overkilled as I need basic matrix capabilities. What is your advice ?

@ doubitchou said in Matrix operations : Actually I'd need some minimal matrix functions like rotation, inverse, flip if by rotation and inverse you don't mean the mathematical terms linked but physical movements of the image in the leds, all these operations can be easily done just by acting on the indexes rather than the content of the matrix. For example: given a matrix[rowCount][colCount] matrix[i][j] mirrored on the vertical axis is matrix[i][colCount-j-1] rotated 90° counter-clockwise is matrix[j][i]

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Matrix operations

Solved General and Desktop

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V VRonin
QImage myMatrix(8,8,QImage::Format_Mono) will create a container of 8 by 8 bits (not bytes).
- myMatrix.fill(0); to turn everything off.
- Point: myMatrix.setPixel(0,0,1);
- Line(1): for(int i=0;i<myMatrix.width();++i) myMatrix.setPixel(0,i,1);
- Column(1): for(int i=0;i<myMatrix.height();++i) myMatrix.setPixel(i,0,1);
- Border: for(int i=0;i<myMatrix.width();++i) {myMatrix.setPixel(0,i,1); myMatrix.setPixel(myMatrix.height()-1,i,1);} for(int i=0;i<myMatrix.height();++i) {myMatrix.setPixel(i,0,1); myMatrix.setPixel(i,myMatrix.width()-1,1);}
- Column Shift(1): myMatrix=myMatrix.transformed(QTransform().translate(1,0));
- Column Shift(-1): myMatrix=myMatrix.transformed(QTransform().translate(-1,0));
- Line Shift(1): myMatrix=myMatrix.transformed(QTransform().translate(0,1));
- Line Shift(-1): myMatrix=myMatrix.transformed(QTransform().translate(0,-1));
- Rotate(1): myMatrix=myMatrix.transformed(QTransform().rotate(270));
- Rotate(-1): myMatrix=myMatrix.transformed(QTransform().rotate(90));
- Invert: myMatrix.invertPixels();
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doubitchou

wrote on last edited by doubitchou

#21

@VRonin

Great answer !, especially to be adapted to my needs. Anyway, I think I should try with Format_Indexed8 instead as I need to store the color values which requires more than a single bit:

0 : off
1 : Green
2 : Red
3 : Orange

(Merci pour cette réponse)
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