bflibrary: Proper way for keeping rescaled sprite sizes

Previous attempt at keeping the scaling size was not very good.
This time we're ensuring sprites are scaled to exactly the
expected size, not by enlarging first pixel, but by adding one
pixel to several first rows of the sprite.

Previously I considered a flag to enable the new scaling, but that
is not how engines should work - app requests size, engine should
deliver. Not deliver something similar, but exactly what was asked.

Author: mefistotelis

bflibrary/include/bfscreen.h

@@ -70,13 +70,24 @@ typedef enum ScreenMode TbScreenMode;
 typedef struct TbSprite TbSprite;
 
 enum TbDrawFlags {
+    /** while drawing sprites, flip them horizontally (left-to-right) */
     Lb_SPRITE_FLIP_HORIZ   = 0x0001,
+    /** while drawing sprites, flip them vertically (top-to-bottom) */
     Lb_SPRITE_FLIP_VERTIC  = 0x0002,
+    /** while drawing sprites, use transparency with sprite data in
+     * upper part of the color mixing array */
     Lb_SPRITE_TRANSPAR4    = 0x0004,
+    /** while drawing sprites, use transparency with sprite data in
+     * lower part of the color mixing array */
     Lb_SPRITE_TRANSPAR8    = 0x0008,
+    /** while drawing sprites and shapes, draw the outline shape only */
     Lb_SPRITE_OUTLINE      = 0x0010,
+    /** while drawing text, horizontally align to left of provided coordinates */
     Lb_TEXT_HALIGN_LEFT    = 0x0020,
+    /** while drawing text or sprites, ignore original colors and use DrawColour
+     * instead */
     Lb_TEXT_ONE_COLOR      = 0x0040,
+    /** while drawing text, horizontally align to right of provided coordinates */
     Lb_TEXT_HALIGN_RIGHT   = 0x0080,
     Lb_TEXT_HALIGN_CENTER  = 0x0100,
     Lb_TEXT_HALIGN_JUSTIFY = 0x0200,

bflibrary/src/general/spr_scl.c

@@ -79,8 +79,18 @@ void LbSpriteSetScalingWidthClippedArray(long * xsteps_arr, long x, long swidth,
         w--;
         pwidth += 2;
     } while (w > 0);
-    // Set the first coordiate again to avoid missing first lines on high size factor
-    xsteps_arr[0] = x;
+    // Increase few pixels size by one to avoid missing first lines on high size factor
+    w = xsteps_arr[0] - x;
+    pwidth = xsteps_arr;
+    while (w > 0)
+    {
+        if (pwidth[0] > 0)
+            pwidth[0]--;
+        if (pwidth[0] + pwidth[1] < gwidth)
+            pwidth[1]++;
+        w--;
+        pwidth += 2;
+    }
 }
 
 void LbSpriteSetScalingWidthClipped(long x, long swidth, long dwidth, long gwidth)
@@ -122,8 +132,16 @@ void LbSpriteSetScalingWidthSimpleArray(long * xsteps_arr, long x, long swidth,
       }
       pwidth += 16;
     } while (w > 0);
-    // Set the first coordiate again to avoid missing first lines on high size factor
-    xsteps_arr[0] = x;
+    // Increase few pixels size by one to avoid missing first lines on high size factor
+    w = xsteps_arr[0] - x;
+    pwidth = xsteps_arr;
+    while (w > 0)
+    {
+        pwidth[0] -= w;
+        pwidth[1]++;
+        w--;
+        pwidth += 2;
+    }
 }
 
 void LbSpriteSetScalingWidthSimple(long x, long swidth, long dwidth)