make output window center its content

Author: malucard

src/gui/gui.cc

@@ -1169,12 +1169,14 @@ void PCSX::GUI::endFrame() {
                 // if output is the only visible window in dockspace, switch to full window render mode automatically
                 outputWindowShown = false;
             }
-            ImVec2 textureSize = ImGui::GetContentRegionAvail();
+            ImVec2 contentRegion = ImGui::GetContentRegionAvail();
+            ImVec2 textureSize = contentRegion;
             if ((m_outputWindowSize.x != textureSize.x) || (m_outputWindowSize.y != textureSize.y)) {
                 m_outputWindowSize = textureSize;
                 m_setupScreenSize = true;
             }
             ImGuiHelpers::normalizeDimensions(textureSize, renderRatio);
+			ImGui::SetCursorPos(ImGui::GetCursorPos() + (contentRegion - textureSize) * 0.5f);
             ImTextureID texture = m_offscreenTextures[m_currentTexture];
             if (g_system->getArgs().isShadersDisabled()) {
                 ImGui::Image(texture, textureSize, ImVec2(0, 0), ImVec2(1, 1));