Nine Patch - Drawing issue

Nine Patch - Drawing issue

DanielH

Member #934

January 2001

Hello,

I'm trying to create a nine patch drawer and am having troubles. The problem is with using al_draw_scaled_bitmap. I am scaling a 1 px wide section of a bitmap and there is bleed over.

{"name":"606365","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/a\/d\/ad6025472b156cc8f3b7f66bfae959ce.png","w":440,"h":220,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/a\/d\/ad6025472b156cc8f3b7f66bfae959ce"}

The box on the left is what is being drawn. The box on the right is what is supposed to happen. If the bitmap's scalable area > 1 then there is no issue.

I attached 'button.bmp'

ALLEGRO_BITMAP *button = al_load_bitmap( "button.bmp" )
dNinePatchBitmap *nine = dNinePatchBitmap::create( button );

nine->draw( 200, 100, 200, 200 );

dNinePatchBitmap.h

#SelectExpand
  1#ifndef _D_NINEPATCHBITMAP_H
  2#define _D_NINEPATCHBITMAP_H
  3
  4#include <allegro5/allegro.h>
  5#include <allegro5/allegro_image.h>
  6
  7class dNinePatchBitmap
  8{
  9public:
 10  static dNinePatchBitmap* create( ALLEGRO_BITMAP *bitmap, int x1 = -1, int y1 = -1, int x2 = -1, int y2 = -1 );
 11  ~dNinePatchBitmap();
 12  void draw( int x, int y, int w, int h );
 13
 14  ALLEGRO_BITMAP *mBitmap;
 15
 16  int mWidth;
 17  int mHeight;
 18  int mStartX1;
 19  int mStartX2;
 20  int mStartY1;
 21  int mStartY2;
 22
 23private:
 24  dNinePatchBitmap();
 25};
 26
 27#endif

dNinePatchBitmap.cpp

#SelectExpand
   1#include "dNinePatchBitmap.h"
   2
   3dNinePatchBitmap::dNinePatchBitmap()
   4{
   5  this->mBitmap = 0;
   6  this->mWidth = 0;
   7  this->mHeight = 0;
   8  this->mStartX1 = 0;
   9  this->mStartX2 = 0;
  10  this->mStartY1 = 0;
  11  this->mStartY2 = 0;
  12}
  13
  14dNinePatchBitmap::~dNinePatchBitmap()
  15{
  16  if ( this->mBitmap )
  17  {
  18    al_destroy_bitmap( this->mBitmap );
  19  }
  20}
  21
  22dNinePatchBitmap* dNinePatchBitmap::create( ALLEGRO_BITMAP *bitmap, int x1, int y1, int x2, int  y2 )
  23{
  24  dNinePatchBitmap* ninePatch = 0;
  25
  26  if ( bitmap )
  27  {
  28    if ( x1 == -1 ) { x1 = 0; };
  29    if ( y1 == -1 ) { y1 = 0; };
  30    if ( x2 == -1 ) { x2 = al_get_bitmap_width( bitmap ) - 1; };
  31    if ( y2 == -1 ) { y2 = al_get_bitmap_height( bitmap ) - 1; };
  32
  33    ninePatch = new dNinePatchBitmap();
  34
  35    if ( ninePatch )
  36    {
  37      ninePatch->mWidth = ( x2 - x1 );
  38      ninePatch->mHeight = ( y2 - y1 );
  39      ninePatch->mBitmap = al_create_bitmap( ninePatch->mWidth, ninePatch->mHeight );
  40
  41      if ( ninePatch->mBitmap )
  42      {
  43        unsigned char r = 0;
  44        unsigned char g = 0;
  45        unsigned char b = 0;
  46        ALLEGRO_BITMAP *target = al_get_target_bitmap();
  47
  48        al_set_target_bitmap( ninePatch->mBitmap );
  49
  50        al_draw_bitmap_region( bitmap, x1 + 1, y1 + 1, ninePatch->mWidth, ninePatch->mHeight, 0, 0, 0 );
  51
  52        al_lock_bitmap( ninePatch->mBitmap, ALLEGRO_PIXEL_FORMAT_ANY, ALLEGRO_LOCK_READONLY );
  53
  54        for ( int i = 0; i <= ninePatch->mWidth; i++ )
  55        {
  56          al_unmap_rgb( al_get_pixel( bitmap, x1 + i, 0 ), &r, &g, &b );
  57
  58          if ( r == 0 && g == 0 && b == 0 )
  59          {
  60            ninePatch->mStartX1 = i - 1;
  61            break;
  62          }
  63        }
  64
  65        for ( int i = ninePatch->mStartX1 + 1; i <= ninePatch->mWidth; i++ )
  66        {
  67          al_unmap_rgb( al_get_pixel( bitmap, x1 + i, 0 ), &r, &g, &b );
  68
  69          if ( !( r == 0 && g == 0 && b == 0 ) )
  70          {
  71            break;
  72          }
  73
  74          ninePatch->mStartX2 = i;
  75        }
  76
  77        for ( int j = 0; j <= ninePatch->mHeight; j++ )
  78        {
  79          al_unmap_rgb( al_get_pixel( bitmap, 0, y1 + j ), &r, &g, &b );
  80
  81          if ( r == 0 && g == 0 && b == 0 )
  82          {
  83            ninePatch->mStartY1 = j - 1;
  84            break;
  85          }
  86        }
  87
  88        for ( int j = ninePatch->mStartY1 + 1; j <= ninePatch->mHeight; j++ )
  89        {
  90          al_unmap_rgb( al_get_pixel( bitmap, 0, y1 + j ), &r, &g, &b );
  91
  92          if ( !( r == 0 && g == 0 && b == 0 ) )
  93          {
  94            break;
  95          }
  96
  97          ninePatch->mStartY2 = j;
  98        }
  99
 100        al_unlock_bitmap( ninePatch->mBitmap );
 101
 102        
 103        al_convert_mask_to_alpha( ninePatch->mBitmap, al_map_rgb( 255, 0, 255 ) );
 104
 105        al_set_target_bitmap( target );
 106      }
 107      else
 108      {
 109        delete ninePatch;
 110      }
 111    }
 112  }
 113
 114  return ninePatch;
 115}
 116
 117void dNinePatchBitmap::draw( int x, int y, int w, int h )
 118{
 119//          s         e
 120//  ........----------.......
 121//  0123456789012345678901234
 122//  1       2         3     
 123
 124  int x1 = 0;
 125  int x2 = this->mStartX1;
 126  int x3 = this->mStartX2;
 127
 128  int y1 = 0;
 129  int y2 = this->mStartY1;
 130  int y3 = this->mStartY2;
 131
 132  int w1 = ( x2 - x1 );
 133  int w2 = ( x3 - x2 );
 134  int w3 = ( this->mWidth - x3 );
 135
 136  int h1 = ( y2 - y1 );
 137  int h2 = ( y3 - y2 );
 138  int h3 = ( this->mHeight - y3 );
 139
 140  int stretchW = w - ( w1 + w3 );
 141  int stretchH = h - ( h1 + h3 );
 142
 143  // upper left
 144  al_draw_bitmap_region( this->mBitmap, x1, y1, w1, h1, x, y, 0 );
 145
 146  // upper right
 147  al_draw_bitmap_region( this->mBitmap, x3, y1, w3, h1, x + w - w3, y, 0 );
 148
 149  // lower left
 150  al_draw_bitmap_region( this->mBitmap, x1, y3, w1, h1, x, y + h - h3, 0 );
 151
 152  // lower right
 153  al_draw_bitmap_region( this->mBitmap, x3, y3, w3, h1, x + w - w3, y + h - h3, 0 );
 154
 155  // upper middle
 156  al_draw_scaled_bitmap( this->mBitmap, x2, y1, w2, h1, x + x2, y, stretchW, h1, 0 );
 157
 158  // middle left
 159  al_draw_scaled_bitmap( this->mBitmap, x1, y2, w1, h2, x, y + y2, w1, stretchH, 0 );
 160
 161
 162  // lower middle
 163  al_draw_scaled_bitmap( this->mBitmap, x2, y3, w2, h3, x + x2, y + h - h3, stretchW, h3, 0 );
 164
 165  // middle right
 166  al_draw_scaled_bitmap( this->mBitmap, x3, y2, w3, h2, x + w - w3, y + y2, w3, stretchH, 0 );
 167
 168  // middle
 169  al_draw_scaled_bitmap( this->mBitmap, x2, y2, w2, h2, x + x2, y + y2, stretchW, stretchH, 0 );
 170}