Mercurial > sdl-ios-xcode
view src/video/bwindow/SDL_BView.h @ 3333:b334b4f7dfa0
[SDL] Bad math in SDL_RenderCopy
Mason Wheeler to sdl
When I tried to render an image using something other than NULL for srcrect, it got horribly distorted. I traced it down to the fact that the math in the rectangle adjustments performed just before the call to renderer->RenderCopy is written inside out. It should look like this:
if (dstrect->w != real_dstrect.w) {
int deltax = (dstrect->x - real_dstrect.x);
int deltaw = (dstrect->w - real_dstrect.w);
real_srcrect.x += (deltax * real_srcrect.w) / dstrect->w;
real_srcrect.w += (deltaw * real_srcrect.w) / dstrect->w;
}
if (dstrect->h != real_dstrect.h) {
int deltay = (dstrect->y - real_dstrect.y);
int deltah = (dstrect->h - real_dstrect.h);
real_srcrect.y += (deltay * real_srcrect.h) / dstrect->h;
real_srcrect.h += (deltah * real_srcrect.h) / dstrect->h;
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sat, 03 Oct 2009 16:23:16 +0000 |
parents | 99210400e8b9 |
children | f7b03b6838cb |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2009 Sam Lantinga This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Sam Lantinga slouken@libsdl.org */ #include "SDL_config.h" #ifndef _SDL_BView_h #define _SDL_BView_h /* This is the event handling and graphics update portion of SDL_BWin */ extern "C" { #include "../../events/SDL_events_c.h" }; class SDL_BView:public BView { public: SDL_BView(BRect frame):BView(frame, "SDL View", B_FOLLOW_ALL_SIDES, (B_WILL_DRAW | B_FRAME_EVENTS)) { image = NULL; xoff = yoff = 0; SetViewColor(0, 0, 0, 0); SetHighColor(0, 0, 0, 0); } virtual ~ SDL_BView() { SetBitmap(NULL); } /* Set drawing offsets for fullscreen mode */ virtual void SetXYOffset(int x, int y) { xoff = x; yoff = y; } virtual void GetXYOffset(int &x, int &y) { x = xoff; y = yoff; } /* The view changed size. If it means we're in fullscreen, we * draw a nice black box in the entire view to get black borders. */ virtual void FrameResized(float width, float height) { BRect bounds; bounds.top = bounds.left = 0; bounds.right = width; bounds.bottom = height; /* Fill the entire view with black */ FillRect(bounds, B_SOLID_HIGH); /* And if there's an image, redraw it. */ if (image) { bounds = image->Bounds(); Draw(bounds); } } /* Drawing portion of this complete breakfast. :) */ virtual void SetBitmap(BBitmap * bitmap) { if (image) { delete image; } image = bitmap; } virtual void Draw(BRect updateRect) { if (image) { if (xoff || yoff) { BRect dest; dest.top = updateRect.top + yoff; dest.left = updateRect.left + xoff; dest.bottom = updateRect.bottom + yoff; dest.right = updateRect.right + xoff; DrawBitmap(image, updateRect, dest); } else { DrawBitmap(image, updateRect, updateRect); } } } virtual void DrawAsync(BRect updateRect) { if (xoff || yoff) { BRect dest; dest.top = updateRect.top + yoff; dest.left = updateRect.left + xoff; dest.bottom = updateRect.bottom + yoff; dest.right = updateRect.right + xoff;; DrawBitmapAsync(image, updateRect, dest); } else { DrawBitmapAsync(image, updateRect, updateRect); } } private: BBitmap * image; int xoff, yoff; }; #endif /* _SDL_BView_h */ /* vi: set ts=4 sw=4 expandtab: */