In this work, we have implemented a convex surface to perform a spatially resolved X-ray reflectivity. This allows imaging the surface along one direction and provides qualitative information on the size, separation, and coverage of the typical features of an inhomogeneously covered surface. Moreover, we can distinguish and quantitatively recover the individual X-ray reflectivity curves from different surface points, and thus deduce their electron density profiles perpendicular to the surface. The length probed along the beam depends on the incident angle and can thus be varied between a few 0.1 to a few mm. The typical spatial resolution of the technique is ~micrometer. The high data acquisition rate allows real-time monitoring of system kinetics with ~millisecond time resolution As a model system, this new method was implemented to monitor the growth of single-layer graphene flakes on liquid copper in real time. The method was enabled by the naturally curved surface of the small liquid drop, which previously used to be regarded as a nuisance in standard XRR experiments. The results were compared to the now well-established method of radiationmode optical microscopy. The reconstruction of the XRR curves from both covered and noncovered parts of the surface allows deducing the flake height/separation gap on the substrate at different stages of the growth, corresponding to different average flake sizes.