discourse/app/assets/javascripts/wizard/components/homepage-preview.js.es6

import { observes } from 'ember-addons/ember-computed-decorators';
import { createPreviewComponent, LOREM, darkLightDiff } from 'wizard/lib/preview';

export default createPreviewComponent(659, 320, {
  logo: null,
  avatar: null,

  @observes('step.fieldsById.homepage_style.value')
  styleChanged() {
    this.triggerRepaint();
  },

  images() {
    return { logo: this.get('wizard').getLogoUrl(), avatar: '/images/wizard/trout.png' };
  },

  paint(ctx, colors, width, height) {
    this.drawFullHeader(colors);
    this.drawPills(colors, height * 0.15);

    if (this.get('step.fieldsById.homepage_style.value') === "latest") {
      this.renderLatest(ctx, colors, width, height);
    } else {
      this.renderCategories(ctx, colors, width, height);
    }
  },

  renderCategories(ctx, colors, width, height) {
    const textColor = darkLightDiff(colors.primary, colors.secondary, 50, 50);
    const margin = height * 0.03;
    const bodyFontSize = height / 440.0;

    const drawLine = (x, y) => {
      ctx.beginPath();
      ctx.strokeStyle = darkLightDiff(colors.primary, colors.secondary, 90, -75);
      ctx.moveTo(margin + x, y);
      ctx.lineTo(margin + x + ((width * 0.9) / 2), y);
      ctx.stroke();
    };

    const cols = [0.025, 0.4, 0.53, 0.58, 0.94].map(c => c * width);

    const headingY = height * 0.33;
    ctx.font = `${bodyFontSize * 0.9}em 'Arial'`;
    ctx.fillStyle = textColor;
    ctx.fillText("Category", cols[0], headingY);
    ctx.fillText("Topics", cols[1], headingY);
    ctx.fillText("Latest", cols[2], headingY);

    let y = headingY + (bodyFontSize * 12);
    ctx.lineWidth = 2;
    drawLine(0, y);
    drawLine(width / 2, y);



    const categoryHeight = height / 6;

    const titles = this.getTitles();

    // Categories
    this.categories().forEach(category => {
      const textPos = y + (categoryHeight * 0.35);
      ctx.font = `Bold ${bodyFontSize * 1.1}em 'Arial'`;
      ctx.fillStyle = colors.primary;
      ctx.fillText(category.name, cols[0], textPos);

      ctx.font = `${bodyFontSize * 0.8}em 'Arial'`;
      ctx.fillStyle = textColor;
      ctx.fillText(titles[0], cols[0] - (margin * 0.25), textPos + (categoryHeight * 0.36));

      ctx.beginPath();
      ctx.moveTo(margin, y);
      ctx.strokeStyle = category.color;
      ctx.lineWidth = 3.5;
      ctx.lineTo(margin, y + categoryHeight);
      ctx.stroke();

      y += categoryHeight;
      ctx.lineWidth = 1;
      drawLine(0, y);
    });

    // Categories - Latest Topics
    const topicHeight = height / 8;
    const avatarSize = topicHeight * 0.7;
    y = headingY + (bodyFontSize * 12);
    ctx.lineWidth = 1;
    ctx.fillStyle = textColor;

    titles.forEach(title => {
      const category = this.categories()[0];
      ctx.font = `${bodyFontSize}em 'Arial'`;
      const textPos = y + (topicHeight * 0.45);
      ctx.fillStyle = textColor;
      this.scaleImage(this.avatar, cols[2], y + (margin * 0.6), avatarSize, avatarSize);
      ctx.fillText(title, cols[3], textPos);

      ctx.font = `Bold ${bodyFontSize}em 'Arial'`;
      ctx.fillText(Math.floor(Math.random() * 90) + 10, cols[4], textPos);
      ctx.font = `${bodyFontSize}em 'Arial'`;
      ctx.fillText(`1h`, cols[4], textPos + (topicHeight * 0.4));

      ctx.beginPath();
      ctx.fillStyle = category.color;
      const badgeSize = topicHeight * 0.1;
      ctx.font = `Bold ${bodyFontSize * 0.5}em 'Arial'`;
      ctx.rect(cols[3] + (margin * 0.5), y + topicHeight * 0.65, badgeSize, badgeSize);
      ctx.fill();

      ctx.fillStyle = colors.primary;
      ctx.fillText(category.name, cols[3] + (badgeSize * 3), y + (topicHeight * 0.76));
      y += topicHeight;

      drawLine(width / 2, y);
    });

  },

  getTitles() {
    return LOREM.split(".").slice(0, 7).map(t => t.substring(0, 40));
  },

  renderLatest(ctx, colors, width, height) {
    const rowHeight = height / 10.0;
    const textColor = darkLightDiff(colors.primary, colors.secondary, 50, 50);
    const bodyFontSize = height / 440.0;

    ctx.font = `${bodyFontSize}em 'Arial'`;

    const margin = height * 0.03;

    const drawLine = y => {
      ctx.beginPath();
      ctx.strokeStyle = darkLightDiff(colors.primary, colors.secondary, 90, -75);
      ctx.moveTo(margin, y);
      ctx.lineTo(width - margin, y);
      ctx.stroke();
    };

    const cols = [0.02, 0.5, 0.65, 0.8, 0.87, 0.93].map(c => c * width);

    // Headings
    const headingY = height * 0.33;

    ctx.fillStyle = textColor;
    ctx.font = `${bodyFontSize * 0.9}em 'Arial'`;
    ctx.fillText("Topic", cols[0], headingY);
    ctx.fillText("Category", cols[1], headingY);
    ctx.fillText("Users", cols[2], headingY);
    ctx.fillText("Replies", cols[3], headingY);
    ctx.fillText("Views", cols[4], headingY);
    ctx.fillText("Activity", cols[5], headingY);

    // Topics
    let y = headingY + rowHeight / 2.6;
    ctx.lineWidth = 2;
    drawLine(y);

    ctx.font = `${bodyFontSize}em 'Arial'`;
    ctx.lineWidth = 1;
    this.getTitles().forEach(title => {
      const textPos = y + (rowHeight * 0.7);
      ctx.fillStyle = textColor;
      ctx.fillText(title, cols[0], textPos);

      const category = this.categories()[0];
      ctx.beginPath();
      ctx.fillStyle = category.color;
      const badgeSize = rowHeight * 0.2;
      ctx.font = `Bold ${bodyFontSize * 0.5}em 'Arial'`;
      ctx.rect(cols[1], y + rowHeight * 0.5, badgeSize, badgeSize);
      ctx.fill();

      ctx.fillStyle = colors.primary;
      ctx.fillText(category.name, cols[1] + (badgeSize * 1.5), y + (rowHeight * 0.65));
      this.scaleImage(this.avatar, cols[2], y + rowHeight * 0.3, rowHeight * 0.5, rowHeight * 0.5);

      ctx.fillStyle = textColor;
      ctx.font = `${bodyFontSize}em 'Arial'`;
      for (let j=3; j<=5; j++) {
        ctx.fillText(Math.floor(Math.random() * 90) + 10, cols[j] + margin, y + (rowHeight * 0.7));
      }
      drawLine(y + (rowHeight * 1));
      y += rowHeight;
    });
  }
});