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Bug 3922

Summary: Viewport and clip rect getters are broken
Product: SDL Reporter: Daniel <daniel.plakhotich>
Component: renderAssignee: Sam Lantinga <slouken>
Status: NEW --- QA Contact: Sam Lantinga <slouken>
Severity: normal    
Priority: P2 CC: sezeroz
Version: 2.0.6   
Hardware: x86_64   
OS: Linux   

Description Daniel 2017-10-26 13:00:46 UTC 
SDL_RenderGetClipRect() and SDL_RenderGetViewport() are broken due to the lossy math. They don't return original rectangles most of the time.

Consider x coordinate 5 and renderer scale 0.1. SDL_RenderSetClipRect() will truncate it ((int)floor(5 * 0.1)), resulting in renderer->clip_rect.x equal to 0.
When SDL_RenderGetClipRect() will return as (int)(0 / 0.1), resulting in 0.

The same happen with scale > 1.0 - it will usually return 1 px smaller coordinate. When SDL_RenderSetClipRect() and SDL_RenderSetClipRect() calls are chained, the error will accumulate. This makes SDL_RenderGetClipRect() and SDL_RenderGetViewport() completely useless.