問73
頻出度★☆☆
PCの画面表示の設定で, 解像度を1,280×960ピクセルの全画面表示から1,024×768ピクセルの全画面表示に変更したとき, ディスプレイの表示状態はどのように変化するか。
平成22年度 春期 ITパスポート試験 問73
This question's explanation and your answers so far.
解説
問 73
Incorrectア
The playback speed of MPEG video (its frame rate) is determined by the specification recorded in the video data itself, and it does not change with the screen resolution setting. Lowering the resolution reduces the number of pixels that have to be drawn and lightens the load on the PC, but that only creates processing headroom; it does not mean playback proceeds faster than it originally should. Even if playback that had been dropping frames becomes smooth, that is not becoming faster but getting closer to the original speed.
- イ
正解 The correct answer is イ. The physical size of the display (the horizontal and vertical dimensions of the screen) does not change when you change the setting. What changes is only the resolution, that is, how many pixels are lined up over that same area. When it is lowered from 1,280×960 to 1,024×768, the pixel count in both width and height drops to 0.8 times, so the same area is filled with fewer pixels, and the apparent size of a single pixel becomes 1.25 times larger. Characters and icons are drawn with a fixed number of pixels in width and height, so once the pixels become larger, they are displayed larger on the screen accordingly. Conversely, raising the resolution makes characters smaller and finer, while the amount of information that can be shown at once increases. It is enough to remember the relationship that resolution and the apparent size of what is displayed are inversely proportional.
Incorrectウ
The number of pixels that can be shown on the screen at one time drops from 1,280×960=1,228,800 to 1,024×768=786,432. In other words, the container that can hold an image at its original size becomes smaller, so a JPEG image that already had to be scaled down to fit will need scaling down even more. This choice has the direction of the change backwards. If you want an image to be displayed without scaling down, you must raise the resolution rather than lower it.
Incorrectエ
The number of colors that can be displayed at the same time (the color depth, that is, the number of bits per pixel) is a setting item separate from resolution, and it does not automatically decrease just because the resolution is lowered. On the contrary, since the required VRAM capacity is determined by resolution × color depth, lowering the resolution frees up memory, and in an environment where the number of colors had been limited by insufficient VRAM, it may even become possible to choose more colors. The statement that the number of colors decreases does not hold.
ここがポイント
- Resolution means the number of pixels lined up across the whole screen. Because the physical size of the display does not change, lowering the resolution makes each pixel larger, so characters and icons look bigger (and coarser); raising the resolution makes each pixel smaller, so characters become smaller (and finer) and the amount of information that can be displayed increases.
- Resolution, the number of colors (color depth), and the frame rate of a video are separate factors. The required VRAM capacity is found as horizontal pixels × vertical pixels × bits per pixel; lowering the resolution reduces the required capacity, but that does not mean the number of colors automatically decreases.
用語