From 22328915ac56464987613cdf52e7316a4ec84dcf Mon Sep 17 00:00:00 2001
From: Thomas Perl <thp@perli.net>
Date: Sat, 1 Sep 2007 19:26:29 +0200
Subject: [PATCH] draw_line() function and pixel getting/setting

Added new function to directly draw a line to the screen,
and define macros: GET_PIXEL_DATA, GET_PIXEL_RGB, SET_PIXEL_RGB.
---
 graphics.c | 24 +++++++++++++++++-------
 graphics.h |  7 +++++++
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/graphics.c b/graphics.c
index f905d86..7848dd3 100644
--- a/graphics.c
+++ b/graphics.c
@@ -22,6 +22,7 @@
  **/
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <math.h>
 
 #include "tennix.h"
@@ -228,11 +229,9 @@ int is_fading() {
 
 int font_get_metrics( unsigned int id, char ch, int* xp, int* wp) {
     SDL_Surface *bitmap;
-    SDL_PixelFormat *fmt;
     int pos, x = -1, w = 0;
     int search_pos = 0, search_x = 0;
     Uint8 red, green, blue;
-    Uint32 pixel;
 
     if( id > GR_COUNT) return 0;
 
@@ -251,14 +250,10 @@ int font_get_metrics( unsigned int id, char ch, int* xp, int* wp) {
         }
 
         bitmap = images[id].data;
-        fmt = bitmap->format;
 
         SDL_LockSurface( bitmap);
         while( search_x < bitmap->w) {
-            pixel = *( (Uint32*)(bitmap->pixels + search_x*fmt->BytesPerPixel));
-            red = (Uint8)(((pixel & fmt->Rmask) >> fmt->Rshift) << fmt->Rloss);
-            green = (Uint8)(((pixel & fmt->Gmask) >> fmt->Gshift) << fmt->Gloss);
-            blue = (Uint8)(((pixel & fmt->Bmask) >> fmt->Bshift) << fmt->Bloss);
+            GET_PIXEL_RGB( bitmap, search_x, 0, &red, &green, &blue);
 
             /* Increase pos counter if we have a "marker" pixel (255,0,255) */
             if( red == 255 && green == 0 && blue == 255) {
@@ -342,3 +337,18 @@ int font_get_string_width( unsigned int id, char* s) {
     return w;
 }
 
+void draw_line( int x1, int y1, int x2, int y2, int r, int g, int b) {
+    float step, dx, dy, x = x1, y = y1;
+    int i;
+
+    step = abs(x2-x1)>abs(y2-y1)?abs(x2-x1):abs(y2-y1);
+    dx = (x2-y1) / step;
+    dy = (y2-y1) / step;
+
+    SDL_LockSurface( screen);
+    for( i=0; i<=step; i++) {
+        SET_PIXEL_RGB( screen, (int)(x+=dx), (int)(y+=dy), r, g, b);
+    }
+    SDL_UnlockSurface( screen);
+}
+
diff --git a/graphics.h b/graphics.h
index 04f9a7e..197fa2c 100644
--- a/graphics.h
+++ b/graphics.h
@@ -30,6 +30,11 @@
 
 #define FADE_DURATION 500
 
+#define GET_PIXEL_DATA(surface,x,y) (*((Uint32*)(surface->pixels + x * surface->format->BytesPerPixel + y * surface->pitch)))
+
+#define GET_PIXEL_RGB(surface,x,y,r,g,b) (SDL_GetRGB( GET_PIXEL_DATA(surface,x,y), surface->format, r, g, b))
+#define SET_PIXEL_RGB(surface,x,y,r,g,b) (GET_PIXEL_DATA(surface,x,y)=SDL_MapRGB(surface->format, r, g, b))
+
 typedef struct {
     SDL_Surface* data;
 } Image;
@@ -74,5 +79,7 @@ int font_draw_char( unsigned int id, char ch, int x_offset, int y_offset);
 void font_draw_string( unsigned int id, char* s, int x_offset, int y_offset, int start, int animation);
 int font_get_string_width( unsigned int id, char* s);
 
+void draw_line( int x1, int y1, int x2, int y2, int r, int g, int b);
+
 #endif
 
-- 
2.11.4.GIT