Computer graphics - Basic definitions summary

1. By
Dr. Mohamed Kazim Khalil

2. Contents
• Computer Graphics
• 2D graphics
• Raster Graphics
• Vector Graphics
• Pixel
• Additive Primary Colors
• Additive Secondary Colors
• Subtractive Primaries
• Three-Dimensional (3D) Computer Graphics
• Computer Animation

3. Computer Graphics
• Computer Graphics is concerned with the generation and ma
manipulation with images.
• Computer Graphics concept refers to graphics created by
computers and the representation and manipulation of pictorial
data by a computer.
• It also includes the hardware and software systems used to make
these images.
•‫يهتم‬‫علم‬‫الرسم‬‫بالحاسب‬‫بتوليد‬‫والتعامل‬‫مع‬‫الصور‬.
•‫مفهوم‬‫الرسم‬‫بالحاسب‬‫بشير‬‫إلى‬‫الصور‬‫المنشأة‬/‫المولدة‬‫باستخدام‬‫الحاسب‬‫اآل‬‫لى‬‫وتمثيل‬
‫ومعالجة‬‫البيانات‬‫المصورة‬‫باستخدام‬‫الحاسب‬.
•‫ويتضمن‬‫ا‬ً‫ض‬‫أي‬‫ذلك‬‫المفهوم‬‫المكونات‬‫المادية‬‫واألنظمة‬‫البرمجية‬‫المستخدمة‬‫ل‬‫عمل‬‫تلك‬
‫الصور‬.

4. 2D graphics
• 2D computer graphics is the computer-based generation of digital
images, mostly from two-dimensional models (such as 2D
geometric models, text, and digital images) and by techniques
specific to them.
• 2D computer graphics are usually split into the two categories of
graphics (Vector and Raster). 2D shapes is like (circles, squares,
triangles, ovals…etc).
•‫الرسم‬‫الثنائى‬‫األبعاد‬‫باستخدام‬‫الحاسب‬‫اآللى‬‫هو‬‫توليد‬‫قائم‬‫على‬‫الحاسب‬‫ل‬‫لصور‬‫الرقمية‬
‫فى‬‫الغالب‬‫من‬‫نماذج‬‫ثنائية‬‫األبعاد‬(‫مثل‬‫النماذج‬‫الهندسية‬‫ثنائية‬،‫األبعاد‬‫وال‬،‫نصوص‬
‫والصور‬‫الرقمية‬)‫ومن‬‫خالل‬‫تقنيات‬‫مخصصة‬‫لها‬.
•‫وعادة‬‫ينقسم‬‫الرسم‬‫الثنائى‬‫األبعاد‬‫باستخدام‬‫الحاسب‬‫إلى‬‫نوعين‬(‫المتجهى‬Vector
‫والنقطى‬Raster).‫األشكال‬‫الثنائية‬‫األبعادة‬‫مثل‬(،‫الدوائر‬،‫المربعات‬،‫المثلثات‬‫األشكال‬
‫البيضاوية‬...‫الخ‬).

5. Raster Graphics
• Raster graphic -also called "Bitmap" graphics- is a picture that is
made from a lot of small square shapes that have color and
position related info, and which are referred to as pixel or dot.
• Raster Graphic is the representation of images as an array of
pixels, and is used for the representation of photographic images.
• Raster graphic is stored as a series of color values in a grid, in
other words, as a collection of pixels.
•‫الرسم‬‫النقطى‬-‫والذى‬‫يطلق‬‫عليها‬‫ا‬ً‫ض‬‫أي‬Bitmap-‫هو‬‫عبارة‬‫عن‬‫صورة‬‫مكونة‬‫من‬
‫مجموعة‬‫مستطيالت‬‫صغيرة‬‫وتتضمن‬‫معلومات‬‫عن‬‫لونها‬،‫وموضعها‬‫والتى‬‫يشار‬‫إليها‬
‫كنقطة‬‫أو‬‫بيكسل‬dots or pixel.
•‫الرسم‬‫النقطى‬‫هو‬‫تمثيل‬‫للصورة‬‫كمصفوفة‬‫من‬،‫النقط‬‫وتستخدم‬‫لتمثيل‬‫ال‬‫صور‬
‫الفوتوغرافية‬.
•‫يتم‬‫تمثيل‬‫الرسم‬‫النقطى‬‫فى‬‫جدول‬‫كسلسلة‬‫من‬‫القيم‬،‫اللونية‬‫وبمعنى‬‫آخر‬‫كمجموعة‬‫من‬
‫النقاط‬pixels.

6. Vector Graphics
• Vector graphic consists of encoding information about shapes and
colors that comprise the image, which can allow for more
flexibility in rendering.
• A vector graphic uses math to draw shapes using points, lines and
curves.
• So, vector graphic has the ability to enlarge without losing quality,
but limited color detail.
•‫يتكون‬‫الرسم‬‫المتجهى‬‫من‬‫معلومات‬‫مرمزة‬‫أو‬‫مكودة‬‫عن‬‫األشكال‬‫واأللوان‬‫التى‬‫تش‬‫كل‬
‫وتكون‬،‫الصورة‬‫والتى‬‫يمكن‬‫أن‬‫تعطى‬‫مرونة‬‫أعلى‬‫فى‬‫إعادة‬‫رسمها‬‫أو‬‫عرضها‬
rendering.
•‫ويستخدم‬‫الرسم‬‫النقطى‬‫الحساب‬‫فى‬‫رسم‬‫األشكال‬‫باستخدام‬‫النقط‬‫والخطوط‬‫و‬‫المنحنيات‬.
•‫ولذا‬،‫فإن‬‫الرسم‬‫المتجهى‬‫لديه‬‫القدرة‬‫على‬‫تكبير‬‫الصورة‬‫دون‬‫أن‬‫تفقد‬‫كفاء‬،‫تها‬‫لكن‬
‫بتفصايل‬‫محدودة‬‫من‬‫األلوان‬.

7. Pixel
• A pixel (or picture element) is a single point in a raster image.
• Pixels are placed on a regular 2-dimensional grid, and are often
represented using dots or squares.
•‫البيكسل‬(‫أو‬‫وحدة‬‫الصورة‬)‫هى‬‫عبارة‬‫عن‬‫نقطة‬‫واحدة‬‫فى‬‫الصورة‬‫النقطية‬.
•‫توضع‬‫النقاط‬Pixels‫فى‬‫شبكة‬‫ثنائية‬،‫األبعاد‬‫وعادة‬‫يتم‬‫تمثيلها‬‫باستخدام‬‫الن‬‫قط‬‫أو‬
‫المستطيالت‬.

8. Additive Primary Colors
• Red, Green and Blue -commonly called RGB- are called the
“Additive Primary Colors”.
• These colors are called additives because you must add/mix the
colors together to create white.
• We obtain other non-primary colors by blending (adding) together
different quantities of Red, Green and Blue light.
•‫األحمر‬‫واألخر‬‫واألزرق‬-‫عادة‬‫ما‬‫تسمى‬RGB-‫يطلق‬‫عليها‬"‫األلوان‬‫األساسية‬
‫المضافة‬".
•‫طلق‬ُ‫ي‬‫على‬‫تلك‬‫األلوان‬"‫مضافة‬"‫ألنه‬‫يجب‬‫إضافة‬/‫مزج‬‫األلوان‬‫ا‬ً‫ع‬‫م‬‫لتكوين‬‫اللون‬
‫األبيض‬.
•‫يمكننا‬‫الحصول‬‫على‬‫األلوان‬‫غير‬‫األولية‬‫من‬‫خالل‬‫مزج‬(‫إضافة‬)‫كميات‬‫مختلفة‬‫ا‬ً‫ع‬‫م‬
‫من‬‫الضوء‬‫األحمر‬‫واألخضر‬‫واألزرق‬.

9. Additive Secondary Colors
• Additive Secondary Colors are produced by mixing two other
additive primary colors together.
• When these additive primary colors are mixed, they produce three
other secondary colors (Cyan, Magenta and Yellow).
•‫األلوان‬‫الثانوية‬‫المضافة‬‫يمكن‬‫إنتاجها‬‫من‬‫خالل‬‫مزج‬‫اثنان‬‫من‬‫األلوان‬‫األساسية‬
‫المضافة‬‫ا‬ً‫ع‬‫م‬.
•‫عند‬‫خلط‬‫هذه‬‫األلوان‬‫األساسية‬،‫المضافة‬‫فإنه‬‫ينتج‬‫ثالثة‬‫ألوان‬‫ثانوية‬‫هى‬(‫الس‬،‫ماوى‬
،‫القرمزى‬‫األصفر‬).

10. Subtractive Primaries
• Subtractive primaries colors depend on mixing the three of (Cyan,
Magenta and Yellow) ink/paint colors.
• Color printer cartridges often contain four colors: Cyan, Magenta,
Yellow, and Black (CMYK).
•‫تعتمد‬‫ألوان‬‫الطرح‬/‫االمتصاص‬‫األولية‬‫على‬‫خلط‬‫أو‬‫مزج‬‫ثالثة‬‫ألوان‬‫الطباعية‬‫أ‬‫و‬
‫الحبرية‬(‫السماوى‬‫واألرجوانى‬‫واألصفر‬).
•‫عادة‬‫ما‬‫تحتوى‬‫عبوات‬‫حبارات‬‫الطابعات‬‫األلوان‬‫على‬‫أربعة‬‫ألوان‬(‫السماوى‬
‫واألرجوانى‬‫واألصفر‬‫واألسود‬CMYK.

11. Three-Dimensional (3D)
Computer Graphics
• 3D graphics are graphics that use a three-dimensional
representation of geometric data that is stored in the computer for
the purposes of performing calculations and rendering 2D images.
• The most common techniques of 3D graphics are more similar to
vector graphics than to raster graphics.
•‫الرسوم‬‫الثالثية‬‫هى‬‫عبارة‬‫عن‬‫رسوم‬‫تستخدم‬‫التمثيل‬‫الثالثى‬‫األبعاد‬‫للب‬‫يانات‬‫الهندسية‬
‫التى‬‫يتم‬‫تخزينها‬‫فى‬‫الحاسب‬‫لغرض‬‫تنفيذ‬‫الحسابات‬‫وإعادة‬‫رسم‬‫وتقديم‬rendering
‫الرسوم‬‫ثنائية‬‫األبعاد‬.
•‫التقنيات‬‫األكثر‬‫ا‬ً‫ع‬‫شيو‬‫فى‬‫الرسوم‬‫ثالثية‬‫األبعاد‬‫هى‬‫أقرب‬‫ما‬‫يكون‬‫إلى‬‫ال‬‫رسوم‬‫المتجهة‬
‫منها‬‫إلى‬‫الرسوم‬‫النقطية‬.

12. Computer Animation
• To "animate" is literally "to give life to". "Animating" is moving
something which can't move itself.
• Animation adds to graphics the dimension of time which increases
the amount of information which can be transmitted.
•‫كلمة‬"animate"‫تعنى‬‫ا‬ً‫ي‬‫لغو‬"‫أن‬‫تعطي‬‫الشىء‬‫حياة‬".‫ومصطلح‬"Animating"‫هو‬
‫أن‬‫تحرك‬‫شىء‬‫ما‬‫ال‬‫يستطيع‬‫التحرك‬‫بنفسه‬.
•‫الحركة‬‫تعطى‬‫للرسوم‬‫ًا‬‫د‬‫بع‬‫فى‬‫الزمان‬‫والذى‬‫يزيد‬‫من‬‫كمية‬‫المعلومات‬‫التى‬‫ي‬‫مكن‬‫نقلها‬.

13. ‫التوفيق‬ ‫وباهلل‬