Method toolDrag

MicropolisCore/src/MicropolisEngine/src/tool.cpp:1516–1592

* Drag a tool from (\a fromX, \a fromY) to (\a toX, \a toY). * @param tool Tool being dragged. * @param fromX Horizontal coordinate of the starting position. * @param fromY Vertical coordinate of the starting position. * @param toX Horizontal coordinate of the ending position. * @param toY Vertical coordinate of the ending position. */

 * @param toY Vertical coordinate of the ending position.
 */
void Micropolis::toolDrag(EditingTool tool,
                            short fromX, short fromY, short toX, short toY)
{
    // Do not drag big tools.
    int toolSize = gToolSize[tool];
    if (toolSize > 1) {
        doTool(tool, toX, toY);

        simPass = 0; // update editors overlapping this one
        invalidateMaps();
        return;
    }

    short dirX = (toX > fromX) ? 1 : -1; // Horizontal step direction.
    short dirY = (toY > fromY) ? 1 : -1; // Vertical step direction.


    if (fromX == toX && fromY == toY) {
        return;
    }

    doTool(tool, fromX, fromY); // Ensure the start position is done.

    // Vertical line up or down
    if (fromX == toX && fromY != toY) {

        while (fromY != toY) {
            fromY += dirY;
            doTool(tool, fromX, fromY);
        }

        simPass = 0; // update editors overlapping this one
        invalidateMaps();
        return;
    }

    // Horizontal line left/right
    if (fromX != toX && fromY == toY) {

        while (fromX != toX) {
            fromX += dirX;
            doTool(tool, fromX, fromY);
        }

        simPass = 0; // update editors overlapping this one
        invalidateMaps();
        return;
    }

    // General case: both X and Y change.

    short dx = absoluteValue(fromX - toX); // number of horizontal steps.
    short dy = absoluteValue(fromY - toY); // number of vertical steps.

    short subX = 0; // Each X step is dy sub-steps.
    short subY = 0; // Each Y step is dx sub-steps.
    short numSubsteps = min(dx, dy); // Number of sub-steps we can do.