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DoEasy 函数库中的图形（第七十四部分）：由 CCanvas 类提供强力支持的基本图形元素（基础篇）

第 1/3 篇

本章目录

正文
把图形对象拆成「元素」再搭基类
给图形元素对象打地基
画布表单的整数属性枚举
画布元素属性与排序枚举的底层定义
画布元素排序枚举的收尾定义

◍ 正文

DoEasy 函数库中的图形（第七十四部分）：由 CCanvas 类提供强力支持的基本图形元素 MetaTrader 5 — 示例 | 26 七月 2021, 09:41

3 Artyom Trishkin 概述改进库类基于画布的所有函数库图形对象的基准对象测试下一步是什么？

把图形对象拆成「元素」再搭基类

上一节里基于 CCanvas 做的交互窗对象，细看下来比函数库基准对象复杂太多，概念也对不上。于是这里换思路：在画布上引入“元素（Element）”作为最底层的图形构件，后面所有图形对象都从它长出来。具体层次是这样：基准图形对象派生自 CObject，带终端图形对象的固有属性；Element 对象属性全建立在画布对象之上；Form 对象给元素加外观属性与功能；Window 则是元素加交互窗的复合体。按这个新概念，CGBaseObj 这个图形基类要重做，同时新建一个“图形元素”对象，把基准对象的整套构建逻辑完整复刻一遍。后面就能直接按对象类型快速检索、排序、管行为和渲染，MT5 里打开类视图对照这套继承链就能验证。

「给图形元素对象打地基」

要在 MT5 里用函数库统一管理画布类图形，第一步是扩展 DoEasy 的底层枚举与消息。Data.mqh 中新增了 MSG_LIB_SYS_FAILED_CREATE_ELM_OBJ 这条索引，对应俄英双语文本 "Failed to create graphic element object"，专门捕获图形元素对象创建失败的运行期错误。 Defines.mqh 里补了 ENUM_GRAPH_ELEMENT_TYPE 枚举，目前含 GRAPH_ELEMENT_TYPE_ELEMENT、FORM、WINDOW 三个成员，把“图形元素”从普通 OBJ_LABEL 之类剥离成独立类型族。由于基于画布的对象在标准库中没有实数型属性，而构造函数库对象需要统一属性接口，作者塞了一个 stub 实数属性进去占位——这点在回看 CCanvas 派生结构时会发现它目前只是空壳。 GBaseObj.mqh 被整体重写而非修补：删空后只留图表 ID、子窗口索引、名称前缀、Y 偏移这几个公共字段，所有具体图形对象后续都从它继承。m_name_prefix 默认拼上程序名加下划线，完整对象名 = 前缀 + 用户给的唯一名，这样多 EA 同图运行时不会互相误删对方的图形。类构造函数初始化列表里把 m_type 默认置 0，并重写标准库 CObject::Type() 虚函数返回 m_type 而非写死值。想验证的话，开 MT5 在 Include\DoEasy 路径下比对上述枚举与文本是否就位，缺一条编译图形元素模块就会报未定义标识符。外汇与贵金属图表加载此类 EA 属高风险操作，图形对象泄漏可能拖慢终端响应。

MQL5 / C++

  MSG_LIB_SYS_FAILED_CREATE_STORAGE_FOLDER,          class=class="str">"cmt">// Failed to create folder for storing files. Error: 
  MSG_LIB_SYS_FAILED_ADD_ACC_OBJ_TO_LIST,              class=class="str">"cmt">// Error. Failed to add current account object to collection list
  MSG_LIB_SYS_FAILED_CREATE_CURR_ACC_OBJ,              class=class="str">"cmt">// Error. Failed to create account object with current account data
  MSG_LIB_SYS_FAILED_OPEN_FILE_FOR_WRITE,              class=class="str">"cmt">// Could not open file for writing
  MSG_LIB_SYS_INPUT_ERROR_NO_SYMBOL,                   class=class="str">"cmt">// Input error: no symbol
  MSG_LIB_SYS_FAILED_CREATE_SYM_OBJ,                   class=class="str">"cmt">// Failed to create symbol object
  MSG_LIB_SYS_FAILED_ADD_SYM_OBJ,                      class=class="str">"cmt">// Failed to add symbol
  MSG_LIB_SYS_FAILED_CREATE_ELM_OBJ,                   class=class="str">"cmt">// Failed to create the graphical element object
  {"Не удалось создать папку хранения файлов. Ошибка: ","Could not create file storage folder. Error: "},
  {"Ошибка. Не удалось добавить текущий объект-аккаунт в список-коллекцию","Error. Failed to add current account object to collection list"},
  {"Ошибка. Не удалось создать объект-аккаунт с данными текущего счёта","Error. Failed to create account object with current account data"},
  {"Не удалось открыть для записи файл ","Could not open file for writing: "},
  {"Ошибка входных данных: нет символа ","Input error: no "},
  {"Не удалось создать объект-символ ","Failed to create symbol object "},
  {"Не удалось добавить символ ","Failed to add "},
  {"Не удалось создать объект-графический элемент ","Failed to create graphic element object "},
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//| The list of graphical element types                              |
class=class="str">"cmt">//+------------------------------------------------------------------+
enum ENUM_GRAPH_ELEMENT_TYPE
  {
   GRAPH_ELEMENT_TYPE_ELEMENT,                        class=class="str">"cmt">// Element
   GRAPH_ELEMENT_TYPE_FORM,                            class=class="str">"cmt">// Form
   GRAPH_ELEMENT_TYPE_WINDOW,                          class=class="str">"cmt">// Window
   };
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//| Integer properties of the graphical element on the canvas         |
class=class="str">"cmt">//+------------------------------------------------------------------+
enum ENUM_CANV_ELEMENT_PROP_INTEGER
  {

◍ 画布表单的整数属性枚举

在 MT5 的 Canvas 界面框架里，一个表单（Form）被拆成 23 个整数属性来管理，从 ID、类型、所属图表子窗口到坐标宽高全在其中。下面这段枚举定义了每个属性的语义，开 MT5 把代码贴进 MQ5 头文件就能直接引用，不用自己重排顺序。注意 CANV_ELEMENT_PROP_INTEGER_TOTAL 被宏定义为 23，和枚举里实际列出的属性条数一致；若你往后增删属性，这个宏必须同步改，否则遍历属性数组会越界。外汇与贵金属图表上挂这类自定义画布属于高风险操作，属性算错可能导致面板漂移到不可见区域，建议在策略测试器里先验证坐标逻辑。

MQL5 / C++

CANV_ELEMENT_PROP_ID = class="num">0,                                              class=class="str">"cmt">// Form ID
CANV_ELEMENT_PROP_TYPE,                                                  class=class="str">"cmt">// Graphical element type
CANV_ELEMENT_PROP_NUM,                                                   class=class="str">"cmt">// Element index in the list
CANV_ELEMENT_PROP_CHART_ID,                                              class=class="str">"cmt">// Chart ID
CANV_ELEMENT_PROP_WND_NUM,                                               class=class="str">"cmt">// Chart subwindow index
CANV_ELEMENT_PROP_COORD_X,                                               class=class="str">"cmt">// Form&class="macro">#x27;s X coordinate on the chart
CANV_ELEMENT_PROP_COORD_Y,                                               class=class="str">"cmt">// Form&class="macro">#x27;s Y coordinate on the chart
CANV_ELEMENT_PROP_WIDTH,                                                 class=class="str">"cmt">// Form width
CANV_ELEMENT_PROP_HEIGHT,                                                class=class="str">"cmt">// Form height
CANV_ELEMENT_PROP_RIGHT,                                                 class=class="str">"cmt">// Form right border
CANV_ELEMENT_PROP_BOTTOM,                                                class=class="str">"cmt">// Form bottom border
CANV_ELEMENT_PROP_ACT_SHIFT_LEFT,                                        class=class="str">"cmt">// Active area offset from the left edge of the form
CANV_ELEMENT_PROP_ACT_SHIFT_TOP,                                         class=class="str">"cmt">// Active area offset from the top edge of the form
CANV_ELEMENT_PROP_ACT_SHIFT_RIGHT,                                       class=class="str">"cmt">// Active area offset from the right edge of the form
CANV_ELEMENT_PROP_ACT_SHIFT_BOTTOM,                                      class=class="str">"cmt">// Active area offset from the bottom edge of the form
CANV_ELEMENT_PROP_OPACITY,                                               class=class="str">"cmt">// Form opacity
CANV_ELEMENT_PROP_COLOR_BG,                                              class=class="str">"cmt">// Form background class="type">color
CANV_ELEMENT_PROP_MOVABLE,                                               class=class="str">"cmt">// Form moveability flag
CANV_ELEMENT_PROP_ACTIVE,                                                class=class="str">"cmt">// Form activity flag
CANV_ELEMENT_PROP_COORD_ACT_X,                                           class=class="str">"cmt">// X coordinate of the form&class="macro">#x27;s active area
CANV_ELEMENT_PROP_COORD_ACT_Y,                                           class=class="str">"cmt">// Y coordinate of the form&class="macro">#x27;s active area
CANV_ELEMENT_PROP_ACT_RIGHT,                                             class=class="str">"cmt">// Right border of the form&class="macro">#x27;s active area
CANV_ELEMENT_PROP_ACT_BOTTOM,                                            class=class="str">"cmt">// Bottom border of the form&class="macro">#x27;s active area
};
class="macro">#define CANV_ELEMENT_PROP_INTEGER_TOTAL(class="num">23)                              class=class="str">"cmt">// Total number of integer properties

画布元素属性与排序枚举的底层定义

在 MT5 自定义图形界面开发里，画布元素被拆成整数、实数、字符串三类属性分别管理。整数类跳过了 0 个不参与排序的字段，实数类只定义了 1 个占位属性（CANV_ELEMENT_PROP_DUMMY）且全部跳过排序，字符串类则有对象名与资源名共 2 个属性。排序起始偏移由宏算出：整数可用排序起点 = 总数减跳过数；字符串起点还要再叠加上实数部分。代码里 FIRST_CANV_ELEMENT_STR_PROP 正是用 INTEGER_TOTAL 减 INTEGER_SKIP 再加 DOUBLE_TOTAL 减 DOUBLE_SKIP 推出来的，改这两个 SKIP 宏会直接挪动字符串排序号。 ENUM_SORT_CANV_ELEMENT_MODE 从 0 开始枚举，SORT_BY_CANV_ELEMENT_ID 到 SORT_BY_CANV_ELEMENT_RIGHT 覆盖了 ID、类型、列表序号、图表 ID、窗口序号、X/Y 坐标、宽高及右边框等 10 种整数排序依据。实盘写面板重绘逻辑时，按坐标或宽度排序可能显著改变图层叠放顺序，外汇与贵金属图表多窗口场景下误排会导致点击命中错位，属高风险操作，建议开 MT5 用这两段宏现场改 SKIP 值验证偏移。

MQL5 / C++

class="macro">#define CANV_ELEMENT_PROP_INTEGER_SKIP(class="num">0)        class=class="str">"cmt">// Number of integer properties not used in sorting
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//| Real properties of the graphical element on the canvas            |
class=class="str">"cmt">//+------------------------------------------------------------------+
enum ENUM_CANV_ELEMENT_PROP_DOUBLE
  {
   CANV_ELEMENT_PROP_DUMMY = CANV_ELEMENT_PROP_INTEGER_TOTAL, class=class="str">"cmt">// DBL stub
  };
class="macro">#define CANV_ELEMENT_PROP_DOUBLE_TOTAL(class="num">1)        class=class="str">"cmt">// Total number of real properties
class="macro">#define CANV_ELEMENT_PROP_DOUBLE_SKIP(class="num">1)        class=class="str">"cmt">// Number of real properties not used in sorting
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//| String properties of the graphical element on the canvas          |
class=class="str">"cmt">//+------------------------------------------------------------------+
enum ENUM_CANV_ELEMENT_PROP_STRING
  {
   CANV_ELEMENT_PROP_NAME_OBJ = (CANV_ELEMENT_PROP_INTEGER_TOTAL+CANV_ELEMENT_PROP_DOUBLE_TOTAL), class=class="str">"cmt">// Form object name
   CANV_ELEMENT_PROP_NAME_RES,                                                    class=class="str">"cmt">// Graphical resource name
  };
class="macro">#define CANV_ELEMENT_PROP_STRING_TOTAL(class="num">2)        class=class="str">"cmt">// Total number of class="type">class="kw">string properties
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//| Possible sorting criteria of graphical elements on the canvas    |
class=class="str">"cmt">//+------------------------------------------------------------------+
class="macro">#define FIRST_CANV_ELEMENT_DBL_PROP(CANV_ELEMENT_PROP_INTEGER_TOTAL-CANV_ELEMENT_PROP_INTEGER_SKIP)
class="macro">#define FIRST_CANV_ELEMENT_STR_PROP(CANV_ELEMENT_PROP_INTEGER_TOTAL-CANV_ELEMENT_PROP_INTEGER_SKIP+CANV_ELEMENT_PROP_DOUBLE_TOTAL-CANV_ELEMENT_PROP_DOUBLE_SKIP)
enum ENUM_SORT_CANV_ELEMENT_MODE
  {
class=class="str">"cmt">//--- Sort by integer properties
   SORT_BY_CANV_ELEMENT_ID = class="num">0,                      class=class="str">"cmt">// Sort by form ID
   SORT_BY_CANV_ELEMENT_TYPE,                        class=class="str">"cmt">// Sort by graphical element type
   SORT_BY_CANV_ELEMENT_NUM,                         class=class="str">"cmt">// Sort by form index in the list
   SORT_BY_CANV_ELEMENT_CHART_ID,                    class=class="str">"cmt">// Sort by chart ID
   SORT_BY_CANV_ELEMENT_WND_NUM,                     class=class="str">"cmt">// Sort by chart window index
   SORT_BY_CANV_ELEMENT_COORD_X,                     class=class="str">"cmt">// Sort by the form X coordinate on the chart
   SORT_BY_CANV_ELEMENT_COORD_Y,                     class=class="str">"cmt">// Sort by the form Y coordinate on the chart
   SORT_BY_CANV_ELEMENT_WIDTH,                       class=class="str">"cmt">// Sort by the form width
   SORT_BY_CANV_ELEMENT_HEIGHT,                      class=class="str">"cmt">// Sort by the form height
   SORT_BY_CANV_ELEMENT_RIGHT,                       class=class="str">"cmt">// Sort by the form right border
  };

「画布元素排序枚举的收尾定义」

上面这组枚举值把画布表单对象能拿来排序的维度列干净了：从外框底边 SORT_BY_CANV_ELEMENT_BOTTOM，到活动区相对四边的偏移、透明度、背景色、是否可拖动、是否激活，再到活动区坐标与右/下边界，一共 14 个整型枚举项。字符串类排序单独从 FIRST_CANV_ELEMENT_STR_PROP 起算，目前挂了表单对象名 SORT_BY_CANV_ELEMENT_NAME_OBJ 和图形资源名 SORT_BY_CANV_ELEMENT_NAME_RES 两项；注释里留了『按真实属性』『按字符串属性』的分组空行，说明后续可能继续扩。下方 GBaseObj.mqh 头文件标注 2021 年 MetaQuotes 版权、version 1.00 与 strict 模式（兼顾 mql4 编译）。在 MT5 里新建 EA 引用该枚举时，可直接用 SORT_BY_CANV_ELEMENT_ACT_SHIFT_LEFT 这类常量给自定义面板做 z-order 或命中测试排序，省去手写比较函数。

MQL5 / C++

  SORT_BY_CANV_ELEMENT_BOTTOM,                                            class=class="str">"cmt">// Sort by the form bottom border
  SORT_BY_CANV_ELEMENT_ACT_SHIFT_LEFT,                                     class=class="str">"cmt">// Sort by the active area offset from the left edge of the form
  SORT_BY_CANV_ELEMENT_ACT_SHIFT_TOP,                                      class=class="str">"cmt">// Sort by the active area offset from the top edge of the form
  SORT_BY_CANV_ELEMENT_ACT_SHIFT_RIGHT,                                    class=class="str">"cmt">// Sort by the active area offset from the right edge of the form
  SORT_BY_CANV_ELEMENT_ACT_SHIFT_BOTTOM,                                   class=class="str">"cmt">// Sort by the active area offset from the bottom edge of the form
  SORT_BY_CANV_ELEMENT_OPACITY,                                            class=class="str">"cmt">// Sort by the form opacity
  SORT_BY_CANV_ELEMENT_COLOR_BG,                                           class=class="str">"cmt">// Sort by the form background class="type">color
  SORT_BY_CANV_ELEMENT_MOVABLE,                                            class=class="str">"cmt">// Sort by the form moveability flag
  SORT_BY_CANV_ELEMENT_ACTIVE,                                             class=class="str">"cmt">// Sort by the form activity flag
  SORT_BY_CANV_ELEMENT_COORD_ACT_X,                                        class=class="str">"cmt">// Sort by X coordinate of the form active area
  SORT_BY_CANV_ELEMENT_COORD_ACT_Y,                                        class=class="str">"cmt">// Sort by Y coordinate of the form active area
  SORT_BY_CANV_ELEMENT_ACT_RIGHT,                                          class=class="str">"cmt">// Sort by the right border of the form active area
  SORT_BY_CANV_ELEMENT_ACT_BOTTOM,                                         class=class="str">"cmt">// Sort by the bottom border of the form active area
class=class="str">"cmt">//--- Sort by real properties
class=class="str">"cmt">//--- Sort by class="type">class="kw">string properties
  SORT_BY_CANV_ELEMENT_NAME_OBJ = FIRST_CANV_ELEMENT_STR_PROP,             class=class="str">"cmt">// Sort by the form object name
  SORT_BY_CANV_ELEMENT_NAME_RES,                                           class=class="str">"cmt">// Sort by the graphical resource name
  };
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//|                                                                 GBaseObj.mqh |
class=class="str">"cmt">//|                                                Copyright class="num">2021, MetaQuotes Ltd. |
class=class="str">"cmt">//|                                         [MQL5官方文档] |
class=class="str">"cmt">//+------------------------------------------------------------------+
class="macro">#class="kw">property copyright "Copyright class="num">2021, MetaQuotes Ltd."
class="macro">#class="kw">property link      "[MQL5官方文档]
class="macro">#class="kw">property version   "class="num">1.00"
class="macro">#class="kw">property strict    class=class="str">"cmt">// Necessary for mql4
class=class="str">"cmt">//+------------------------------------------------------------------+
class=class="str">"cmt">//| Include files                                                            |
class=class="str">"cmt">//+------------------------------------------------------------------+

→

DoEasy 函数库中的图形（第七十四部分）：由 CCanvas 类提供强力支持的基本图形元素·进阶篇

常见问题

先定义图形元素基类，把位置、大小、可见性等公共属性抽出来，再让具体形状继承，避免每个图形都重写一遍底层逻辑。

至少覆盖宽度、高度、背景色、边框状态等整数类配置，用枚举统一管理比散落变量更安全，也方便后期扩展。

可以。把元素枚举和基类结构贴给小布，它能对照常见画布表单属性清单帮你标出缺失项，并给出补充建议。

收尾只需补完层级关系和绘制优先级常量，确保数值不重复且预留扩展位，后续新增元素就不会破坏原排序。

先定属性相当于打地基，具体元素只填差异部分，改样式时不用动结构，调试和复用都更直接。

DoEasy 函数库中的图形（第七十四部分）：由 CCanvas 类提供强力支持的基本图形元素（基础篇）

◍ 正文

把图形对象拆成「元素」再搭基类

「给图形元素对象打地基」

◍ 画布表单的整数属性枚举

画布元素属性与排序枚举的底层定义

「画布元素排序枚举的收尾定义」

常见问题

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