common: move measure and viewport configuration into Document

namespace plotfx {

Document::Document() :

    width({Unit::PX, 1200}),

    height({Unit::PX, 600}) {}

ReturnCode buildDocument(

    const PropertyList& plist,

    Document* tree) {

 */

#pragma once

#include "utils/return_code.h"

#include "graphics/measure.h"

#include "element.h"

namespace plotfx {

class Layer;

struct Document {

  Document();

  MeasureTable measures;

  Measure width;

  Measure height;

  std::vector<ElementRef> roots;

};

Layer::Layer(

    double w,

    double h,

    double rem /* = 12 */,

    double dpi /* = 96 */) :

    const MeasureTable& m /* = MeasureTable{} */) :

    width(w),

    height(h),

    measures{.dpi = dpi, .rem = rem},

    measures(m),

    //pixmap(PixelFormat::RGBA8, w, h),

    text_shaper(dpi),

    rasterizer(w, h, measures) {}

    text_shaper(m.dpi),

    rasterizer(w, h, m) {}

Layer::~Layer() {}

struct Layer {

  Layer();

  Layer(double width, double height, double rem = 12, double dpi = 96);

  Layer(double width, double height, const MeasureTable& measures = MeasureTable{});

  ~Layer();

  Layer(const Layer&) = delete;

  Layer& operator=(const Layer&) = delete;

};

struct MeasureTable {

  MeasureTable() : dpi(96), rem(12) {}

  double dpi;

  double rem;

};