gg

    private void jPanel1MousePressed(java.awt.event.MouseEvent evt) {
     this.pirmX = evt.getX()-canvas.offsetX;
     this.pirmY = -(evt.getY()-canvas.offsetY);
     this.otrX = this.pirmX;
     this.otrY = this.pirmY;
     this.dragging = true;
     int a = this.pirmX, b= this.pirmY;
     canvas.showBlackPixel(a, b);
    }

    private void jPanel1MouseDragged(java.awt.event.MouseEvent evt) {

        if(!dragging){
            return;
        }
        int a0 = this.pirmX;
        int a1 = this.otrX;
        int b0 = this.pirmY;
        int b1 = this.otrY;
       int xn= a0, yn=b0, dx=Math.abs(a1-a0), dy=Math.abs(b1-b0);
       int xi,yi;

        if(a0<a1){    //Pārbauda taisnes virzienu
            xi=1;
        }else{
            xi=-1;
        }
        if(b0<b1){  //ja y1<mazaks neka pedejais, tad vajag palielināt y,
            yi=1;   //bet ja pirma punkta vertiba ir lielaka neka pedeja, tad vajag samazinat
        }else{
            yi=-1;
        }
        canvas.showColorPixel(a0, b0, myWhite);

        int pn;
        int i = -1;
        if(dx>=dy){
            pn=2*dy-dx;
            i++;
            while(xn!=a1){
                if(pn>0){
                    xn=xn+xi;
                    yn=yn+yi;
                    pn=pn+2*dy-2*dx;
                    i++;
                }else{
                    xn=xn+xi;
                    pn=pn+2*dy;
                    i++;
                }
                canvas.showColorPixel(xn, yn, myWhite);
            }
        }else{
            pn=2*dx-dy;
            i++;
            while(yn!=a1){
                if(pn>0){
                    xn=xn+xi;
                    yn=yn+yi;
                    pn=pn+2*dx-2*dy;
                    i++;
                }else{
                    yn=yn+yi;
                    pn=pn+2*dx;
                    i++;
                }
                canvas.showColorPixel(xn, yn, myWhite);
            }
        }
        this.otrX = evt.getX() - canvas.offsetX;
        this.otrY = -(evt.getY() - canvas.offsetY);
        a1 = this.otrX;
        b1 = this.otrY;
        a0 = this.pirmX;
        b0 = this.pirmY;
        xn= a0; yn=b0; dx=Math.abs(a1-a0); dy=Math.abs(b1-b0);
         if(a0<a1){    //Pārbauda taisnes virzienu
            xi=1;
        }else{
            xi=-1;
        }
        if(b0<b1){  //ja y1<mazaks neka pedejais, tad vajag palielināt y,
            yi=1;   //bet ja pirma punkta vertiba ir lielaka neka pedeja, tad vajag samazinat
        }else{
            yi=-1;
        }
        canvas.showBlackPixel(a0,b0);
        if(dx>=dy){
            pn=2*dy-dx;
            i++;
            while(xn!=a1){
                if(pn>0){
                    xn=xn+xi;
                    yn=yn+yi;
                    pn=pn+2*dy-2*dx;
                    i++;
                }else{
                    xn=xn+xi;
                    pn=pn+2*dy;
                    i++;
                }
                canvas.showBlackPixel(xn,yn);
            }
        }else{
            pn=2*dx-dy;
            i++;
            while(yn!=a1){
                if(pn>0){
                    xn=xn+xi;
                    yn=yn+yi;
                    pn=pn+2*dx-2*dy;
                    i++;
                }else{
                    yn=yn+yi;
                    pn=pn+2*dx;
                    i++;
                }
                canvas.showBlackPixel(xn,yn);
            }
        }


    }

    private void jPanel1MouseReleased(java.awt.event.MouseEvent evt) {

        if(!dragging){
            return;
        }
        int a0 = this.pirmX;
        int a1 = this.otrX;
        int b0 = this.pirmX;
        int b1 = this.otrX;
       int xn= a0, yn=b0, dx=Math.abs(a1-a0), dy=Math.abs(b1-b0);
       int xi,yi;

        if(a0<a1){    //Pārbauda taisnes virzienu
            xi=1;
        }else{
            xi=-1;
        }
        if(a0<a1){  //ja y1<mazaks neka pedejais, tad vajag palielināt y,
            yi=1;   //bet ja pirma punkta vertiba ir lielaka neka pedeja, tad vajag samazinat
        }else{
            yi=-1;
        }
        canvas.showColorPixel(a0, b0, myWhite);

        int pn;
        int i = -1;
        if(dx>=dy){
            pn=2*dy-dx;
            i++;
            while(xn!=a1){
                if(pn>0){
                    xn=xn+xi;
                    yn=yn+yi;
                    pn=pn+2*dy-2*dx;
                    i++;
                }else{
                    xn=xn+xi;
                    pn=pn+2*dy;
                    i++;
                }
                canvas.showColorPixel(xn, yn, myWhite);
            }
        }else{
            pn=2*dx-dy;
            i++;
            while(yn!=a1){
                if(pn>0){
                    xn=xn+xi;
                    yn=yn+yi;
                    pn=pn+2*dx-2*dy;
                    i++;
                }else{
                    yn=yn+yi;
                    pn=pn+2*dx;
                    i++;
                }
                canvas.showColorPixel(xn, yn, myWhite);
            }
        }
        a1 = evt.getX() - canvas.offsetX;
        b1 = -(evt.getY() - canvas.offsetY);
        xn= a0; yn=b0; dx=Math.abs(a1-a0); dy=Math.abs(b1-b0);
        if(a0<a1){    //Pārbauda taisnes virzienu
            xi=1;
        }else{
            xi=-1;
        }
        if(a0<a1){  //ja y1<mazaks neka pedejais, tad vajag palielināt y,
            yi=1;   //bet ja pirma punkta vertiba ir lielaka neka pedeja, tad vajag samazinat
        }else{
            yi=-1;
        }

        canvas.showBlackPixel(a0,b0);

        if(dx>=dy){
            pn=2*dy-dx;
            i++;
            while(xn!=a1){
                if(pn>0){
                    xn=xn+xi;
                    yn=yn+yi;
                    pn=pn+2*dy-2*dx;
                    i++;
                }else{
                    xn=xn+xi;
                    pn=pn+2*dy;
                    i++;
                }
                canvas.showBlackPixel(xn,yn);
            }
        }else{
            pn=2*dx-dy;
            i++;
            while(yn!=a1){
                if(pn>0){
                    xn=xn+xi;
                    yn=yn+yi;
                    pn=pn+2*dx-2*dy;
                    i++;
                }else{
                    yn=yn+yi;
                    pn=pn+2*dx;
                    i++;
                }
                canvas.showBlackPixel(xn,yn);
            }
        }

    }