Hello Shiv09,
It is normally very easy to change the resolution of a TouchGFX project when it is using LTDC, but it is unfortunately a bit more complicated for the board template project you have based your project on.
Normally, the resolution should just be changed in STM32CubeMX by setting the size of LTDC->Layer0 to the desired resolution. When regenerating code, this will both change the hardware setup code and configure the TouchGFX project to the new resolution.
The display on the STM32H747i-Eval board is unfortunately a tricky to use and our template project for this board is therefore quite complicated. It is therefore also more complicated to change the resolution. If you already updated the "hardware code" to work with the new display, you just need to configure TouchGFX to the correct width and height. This should be done in your STM32CubeMX project under the Middlewares->X-CUBE-TOUCHGFX tab. After regenerating code in CubeMX, the TouchGFX Designer canvas should automatically change to the new resolution.
TouchGFX designer does not modify your GUI screens when changing the resolution, so you manually need to scale and move your widgets to fit the new resolution,
Best regards,
Peter