[AGG] Trouble initializing buffer in constructor

[KarthikRIyer <Kar...@ya...>]

Hi,

I want to initialize the buffer that I want to use inside a constructor. But
doing that is giving me a segmentation fault as follows when run using gdb:

Program received signal SIGSEGV, Segmentation fault.
0x0000555555588680 in agg::blender_rgb<agg::rgba8,
agg::order_rgb>::blend_pix (p=0x264d4b42129b <error: Cannot access memory at
address 0x264d4b42129b>, cr=0, cg=0, cb=0, alpha=34, cover=34)
    at /home/karthik/swiftplot/framework/AGG/include/agg_pixfmt_rgb.h:91
91	            p[Order::R] += (value_type)(((cr - p[Order::R]) * alpha) >>
base_shift);


But everything works fine when I initialize it in the class directly.

Here's the initializing part of the code:

class Plot{

  public:
    agg::rasterizer_scanline_aa<> m_ras;
    agg::scanline_p8              m_sl_p8;
    agg::line_cap_e roundCap = agg::round_cap;
    renderer_aa ren_aa;
    int pngBufferSize = 0;

    unsigned char* buffer;


    agg::int8u*           m_pattern;
    agg::rendering_buffer m_pattern_rbuf;
    renderer_base_pre rb_pre;

    Plot(float width, float height, float subW, float subH){
      frame_width = width;
      frame_height = height;
      sub_width = subW;
      sub_height = subH;
      buffer = new unsigned char[frame_width*frame_height*3];
      agg::rendering_buffer rbuf = agg::rendering_buffer(buffer,
frame_width, frame_height, -frame_width*3);
      pixfmt pixf = pixfmt(rbuf);
      renderer_base rb = renderer_base(pixf);
      ren_aa = renderer_aa(rb);
      pixfmt_pre pixf_pre(rbuf);
      rb_pre = renderer_base_pre(pixf_pre);
    }

How can I solve this? I need to set the buffer size in the constructor so
that the end user can choose he size of the image he/she wants.

Thanks,
Karthik




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