At guiInit, the DLL records the chart window DPI and scales placement and fonts from logical to physical pixels. Getters for position/size return logical values.

int guiLogicalToPx(int gui_id, int logical_value);
int guiPxToLogical(int gui_id, int physical_value);

Use these to align GuiPro objects with native MT4 chart objects (whose coordinates MT4 treats as logical). Returns input unchanged when gui_id is unknown or DPI is 96.