[Octave-bug-tracker] [bug #42435] cropped image elements don't display

[Rik]

Follow-up Comment #2, bug #42435 (project octave):

This is a known issue.  The code in gl-render.cc for draw_image has the
following:


    // OpenGL won't draw any of the image if its origin is outside the
    // viewport/clipping plane so we must do the clipping ourselves.

    int j0, j1, i0, i1;
    j0 = 0, j1 = w;
    i0 = 0, i1 = h;

    float im_xmin = x(0) - nor_dx/2;
    float im_xmax = x(1) + nor_dx/2;
    float im_ymin = y(0) - nor_dy/2;
    float im_ymax = y(1) + nor_dy/2;
    if (props.is_clipping ()) // clip to axes
      {
        if (im_xmin < xmin)
          j0 += (xmin - im_xmin)/nor_dx + 1;
        if (im_xmax > xmax)
          j1 -= (im_xmax - xmax)/nor_dx;

        if (im_ymin < ymin)
          i0 += (ymin - im_ymin)/nor_dy + 1;
        if (im_ymax > ymax)
          i1 -= (im_ymax - ymax)/nor_dy;
      }
    else // clip to viewport
      {
        GLfloat vp[4];
        glGetFloatv (GL_VIEWPORT, vp);
        // FIXME: actually add the code to do it!
      }


Any change would have to start here.


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